<Page>

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM N-CSR

                   CERTIFIED SHAREHOLDER REPORT OF REGISTERED
                         MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number: 811-06530

Active Assets California Tax-Free Trust
               (Exact name of registrant as specified in charter)

1221 Avenue of the Americas, New York, New York 10020
      (Address of principal executive offices)                  (Zip code)

Ronald E. Robison
1221 Avenue of the Americas, New York, New York 10020
                     (Name and address of agent for service)

Registrant's telephone number, including area code: 212-762-4000

Date of fiscal year end: June 30, 2005

Date of reporting period: June 30, 2005


Item 1 - Report to Shareholders
<Page>

WELCOME, SHAREHOLDER:

IN THIS REPORT, YOU'LL LEARN ABOUT HOW YOUR INVESTMENT IN ACTIVE ASSETS
CALIFORNIA TAX-FREE TRUST PERFORMED DURING THE ANNUAL PERIOD. WE WILL PROVIDE AN
OVERVIEW OF THE MARKET CONDITIONS, AND DISCUSS SOME OF THE FACTORS THAT AFFECTED
PERFORMANCE DURING THE REPORTING PERIOD. IN ADDITION, THIS REPORT INCLUDES THE
FUND'S FINANCIAL STATEMENTS AND A LIST OF FUND INVESTMENTS.


THIS MATERIAL MUST BE PRECEDED OR ACCOMPANIED BY A PROSPECTUS FOR THE FUND BEING
OFFERED.

MARKET FORECASTS PROVIDED IN THIS REPORT MAY NOT NECESSARILY COME TO PASS. THERE
IS NO ASSURANCE THAT A MUTUAL FUND WILL ACHIEVE ITS INVESTMENT OBJECTIVE. AN
INVESTMENT IN A MONEY MARKET FUND IS NOT INSURED OR GUARANTEED BY THE FEDERAL
DEPOSIT INSURANCE CORPORATION OR ANY OTHER GOVERNMENT AGENCY. ALTHOUGH THE FUND
SEEKS TO PRESERVE THE VALUE OF AN INVESTMENT AT $1.00 PER SHARE, IT IS POSSIBLE
TO LOSE MONEY BY INVESTING IN THE FUND. PLEASE SEE THE PROSPECTUS FOR MORE
COMPLETE INFORMATION ON INVESTMENT RISKS.

<Page>

FUND REPORT

FOR THE YEAR ENDED JUNE 30, 2005

MARKET CONDITIONS

Against the backdrop of economic improvement and rising oil prices, the Federal
Open Market Committee (the "Fed") raised the federal funds target rate in each
of its meetings during the 12-month reporting period. Through this "measured"
series of eight 25 basis point increases, the Fed brought the target rate from
1.25 percent at the start of the reporting to 3.25 percent at the close. The
yields of short-term instruments rose in response to the Fed's actions. Within
the municipal money market, variable-rate securities performed particularly
well. Variable-rate securities quickly adjust their yields in response to
changes in interest rates, a desirable characteristic in a rising-rate
environment.

The State of California continued to show signs of improvement. Unemployment
moved downward, while residential real estate markets strengthened. The
California government's measures to stem budget deficits have been met with
approval by investors while growth in personal and corporate income taxes has
also contributed to a more stable credit outlook. However, the State still faces
many challenges to achieving fiscal balance. For example, tax reforms could
curtail revenues and the prospect of steep future Medicaid outlays cast a
shadow.

PERFORMANCE ANALYSIS

As of June 30, 2005, Active Assets California Tax-Free Trust had net assets of
approximately $704 million and an average portfolio maturity of 15 days. For the
12-month period ended June 30, 2005, the Fund provided a total return of 1.17
percent. For the seven-day period ended June 30, 2005, the Fund provided an
effective annualized yield of 1.78 percent and a current yield of 1.76 percent,
while its 30-day moving average yield for June was 1.71 percent. PAST
PERFORMANCE IS NO GUARANTEE OF FUTURE RESULTS.

We continued to manage the Fund conservatively in anticipation of continued
interest-rate increases. We favored securities with daily or weekly rate reset
features; this strategy positioned the Fund to benefit speedily as rates
increased. Additionally, within the Fund's fixed-rate portfolio, we emphasized
commercial paper with maturities of one to three months and to a lesser extent,
municipal notes and bonds in the six-to-nine month range. Meanwhile, we
decreased exposure to notes with one-year maturities, to avoid hindering the
Fund's ability to redeploy assets in higher yielding securities as they came to
market. We sought opportunities in financings for smaller municipalities whose
issues often offer more attractive yields than those of larger municipal
government entities.

                                        2
<Page>

PORTFOLIO COMPOSITION

<Table>
                                            
   Variable Rate Municipal Obligations         82.8%
   Tax-Exempt Commercial Paper                  9.5
   Municipal Notes                              7.7
</Table>

MATURITY SCHEDULE

<Table>
                                            
     1 - 30 Days                               95.4%
    31 - 60 Days                                2.2
    61 - 90 Days                                 --
    91 - 120 Days                               0.6
   121 + Days                                   1.8
</Table>

DATA AS OF JUNE 30, 2005. SUBJECT TO CHANGE DAILY. ALL PERCENTAGES FOR PORTFOLIO
COMPOSITION AND MATURITY SCHEDULE ARE AS A PERCENTAGE OF TOTAL INVESTMENTS.
THESE DATA ARE PROVIDED FOR INFORMATIONAL PURPOSES ONLY AND SHOULD NOT BE DEEMED
A RECOMMENDATION TO BUY OR SELL THE SECURITIES MENTIONED. MORGAN STANLEY IS A
FULL-SERVICE SECURITIES FIRM ENGAGED IN SECURITIES TRADING AND BROKERAGE
ACTIVITIES, INVESTMENT BANKING, RESEARCH AND ANALYSIS, FINANCING AND FINANCIAL
ADVISORY SERVICES.

INVESTMENT STRATEGY

THE FUND INVESTS IN HIGH QUALITY, SHORT-TERM SECURITIES THAT ARE NORMALLY
MUNICIPAL OBLIGATIONS THAT PAY INTEREST EXEMPT FROM FEDERAL AND CALIFORNIA
INCOME TAXES. THE FUND'S "INVESTMENT ADVISER," MORGAN STANLEY INVESTMENT
ADVISORS INC., SEEKS TO MAINTAIN THE FUND'S SHARE PRICE AT $1.00. THE SHARE
PRICE REMAINING STABLE AT $1.00 MEANS THAT THE FUND WOULD PRESERVE THE PRINCIPAL
VALUE OF YOUR INVESTMENT.

AN INVESTMENT IN THE FUND IS NOT INSURED OR GUARANTEED BY THE FEDERAL DEPOSIT
INSURANCE CORPORATION OR ANY OTHER GOVERNMENT AGENCY. ALTHOUGH THE FUND SEEKS TO
PRESERVE THE VALUE OF YOUR INVESTMENT AT $1.00 PER SHARE, IT IS POSSIBLE TO LOSE
MONEY BY INVESTING IN THE FUND.

FOR MORE INFORMATION ABOUT PORTFOLIO HOLDINGS

EACH MORGAN STANLEY FUND PROVIDES A COMPLETE SCHEDULE OF PORTFOLIO HOLDINGS IN
ITS SEMIANNUAL AND ANNUAL REPORTS WITHIN 60 DAYS OF THE END OF THE FUND'S SECOND
AND FOURTH FISCAL QUARTERS BY FILING THE SCHEDULE ELECTRONICALLY WITH THE
SECURITIES AND EXCHANGE COMMISSION (SEC). THE SEMIANNUAL REPORTS ARE FILED ON
FORM N-CSRS AND THE ANNUAL REPORTS ARE FILED ON FORM N-CSR. MORGAN STANLEY ALSO
DELIVERS THE SEMIANNUAL AND ANNUAL REPORTS TO FUND SHAREHOLDERS AND MAKES THESE
REPORTS AVAILABLE ON ITS PUBLIC WEB SITE, www.morganstanley.com. EACH MORGAN
STANLEY FUND ALSO FILES A COMPLETE SCHEDULE OF PORTFOLIO HOLDINGS WITH THE SEC
FOR THE FUND'S FIRST AND THIRD FISCAL QUARTERS ON FORM N-Q. MORGAN STANLEY DOES
NOT DELIVER THE REPORTS FOR THE FIRST AND THIRD FISCAL QUARTERS TO SHAREHOLDERS,
NOR ARE THE REPORTS POSTED TO THE MORGAN STANLEY PUBLIC WEB SITE. YOU MAY,
HOWEVER, OBTAIN THE FORM N-Q FILINGS (AS WELL AS THE FORM N-CSR AND N-CSRS
FILINGS) BY

                                        3
<Page>

ACCESSING THE SEC'S WEB SITE, http://www.sec.gov. YOU MAY ALSO REVIEW AND COPY
THEM AT THE SEC'S PUBLIC REFERENCE ROOM IN WASHINGTON, DC. INFORMATION ON THE
OPERATION OF THE SEC'S PUBLIC REFERENCE ROOM MAY BE OBTAINED BY CALLING THE SEC
AT (800) SEC-0330. YOU CAN ALSO REQUEST COPIES OF THESE MATERIALS, UPON PAYMENT
OF A DUPLICATING FEE, BY ELECTRONIC REQUEST AT THE SEC'S E-MAIL ADDRESS
(publicinfo@sec.gov) OR BY WRITING THE PUBLIC REFERENCE SECTION OF THE SEC,
WASHINGTON, DC 20549-0102.

HOUSEHOLDING NOTICE

TO REDUCE PRINTING AND MAILING COSTS, THE FUND ATTEMPTS TO ELIMINATE DUPLICATE
MAILINGS TO THE SAME ADDRESS. THE FUND DELIVERS A SINGLE COPY OF CERTAIN
SHAREHOLDER DOCUMENTS, INCLUDING SHAREHOLDER REPORTS, PROSPECTUSES AND PROXY
MATERIALS, TO INVESTORS WITH THE SAME LAST NAME WHO RESIDE AT THE SAME ADDRESS.
YOUR PARTICIPATION IN THIS PROGRAM WILL CONTINUE FOR AN UNLIMITED PERIOD OF TIME
UNLESS YOU INSTRUCT US OTHERWISE. YOU CAN REQUEST MULTIPLE COPIES OF THESE
DOCUMENTS BY CALLING (800) 350-6414, 8:00 A.M. TO 8:00 P.M., ET. ONCE OUR
CUSTOMER SERVICE CENTER HAS RECEIVED YOUR INSTRUCTIONS, WE WILL BEGIN SENDING
INDIVIDUAL COPIES FOR EACH ACCOUNT WITHIN 30 DAYS.

                                        4
<Page>

EXPENSE EXAMPLE

As a shareholder of the Fund, you incur ongoing costs, including management
fees; distribution and service (12b-1) fees; and other Fund expenses. This
example is intended to help you understand your ongoing costs (in dollars) of
investing in the Fund and to compare these costs with the ongoing costs of
investing in other mutual funds.

The example is based on an investment of $1,000 invested at the beginning of the
period and held for the entire period 01/01/05 - 06/30/05.

ACTUAL EXPENSES

The first line of the table below provides information about actual account
values and actual expenses. You may use the information in this line, together
with the amount you invested, to estimate the expenses that you paid over the
period. Simply divide your account value by $1,000 (for example, an $8,600
account value divided by $1,000 = 8.6), then multiply the result by the number
in the first line under the heading entitled "Expenses Paid During Period" to
estimate the expenses you paid on your account during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The second line of the table below provides information about hypothetical
expenses based on the Fund's actual expense ratio and an assumed rate of return
of 5% per year before expenses, which is not the Fund's actual return. The
hypothetical account values and expenses may not be used to estimate the actual
ending account balance or expenses you paid for the period. You may use this
information to compare the ongoing cost of investing in the Fund and other
funds. To do so, compare this 5% hypothetical example with the 5% hypothetical
examples that appear in the shareholder reports of the other funds.

Please note that the expenses shown in the table are meant to highlight your
ongoing costs only. Therefore, the second line of the table is useful in
comparing ongoing costs, and will not help you determine the relative total cost
of owning different funds that have transactional costs, such as sales charges
(loads), and redemption fees, or exchange fees.

<Table>
<Caption>
                                                                     BEGINNING          ENDING           EXPENSES PAID
                                                                   ACCOUNT VALUE     ACCOUNT VALUE      DURING PERIOD *
                                                                   -------------     -------------      ---------------
                                                                                                          01/01/05 -
                                                                     01/01/05          06/30/05            06/30/05
                                                                   -------------     -------------      ---------------
                                                                                                  
Actual (0.76% return)                                                $  1,000.00      $   1,007.60         $   3.09
Hypothetical (5% annual return before expenses)                      $  1,000.00      $   1,021.72         $   3.11
</Table>

- ----------
  *  EXPENSES ARE EQUAL TO THE FUND'S ANNUALIZED EXPENSE RATIO OF 0.62%
     MULTIPLIED BY THE AVERAGE ACCOUNT VALUE OVER THE PERIOD, MULTIPLIED BY
     181/365 (TO REFLECT THE ONE-HALF YEAR PERIOD).

                                        5
<Page>

INVESTMENT ADVISORY AGREEMENT APPROVAL

NATURE, EXTENT AND QUALITY OF SERVICES

The Board reviewed and considered the nature and extent of the investment
advisory services provided by the Investment Adviser under the Advisory
Agreement, including portfolio management, investment research and fixed income
securities trading. The Board also reviewed and considered the nature and extent
of the non-advisory, administrative services provided by the Fund's
Administrator under the Administration Agreement, including accounting,
clerical, bookkeeping, compliance, business management and planning, and the
provision of supplies, office space and utilities. (The Investment Adviser and
the Administrator together are referred to as the "Adviser" and the Advisory and
Administration Agreements together are referred to as the "Management
Agreement.") The Board also compared the nature of the services provided by the
Adviser with similar services provided by non-affiliated advisers as reported to
the Board by Lipper Inc. ("Lipper").

The Board reviewed and considered the qualifications of the portfolio managers,
the senior administrative managers and other key personnel of the Adviser who
provide the administrative and investment advisory services to the Fund. The
Board determined that the Adviser's portfolio managers and key personnel are
well qualified by education and/or training and experience to perform the
services in an efficient and professional manner. The Board concluded that the
nature and extent of the advisory and administrative services provided were
necessary and appropriate for the conduct of the business and investment
activities of the Fund. The Board also concluded that the overall quality of the
advisory and administrative services was satisfactory.

PERFORMANCE RELATIVE TO COMPARABLE FUNDS MANAGED BY OTHER ADVISERS

The Board reviewed the Fund's performance for the one-, three- and five-year
periods ended November 30, 2004, as shown in reports provided by Lipper (the
"Lipper Reports"), compared to the performance of comparable funds selected by
Lipper (the "performance peer group"), and noted that the Fund's performance was
lower than its performance peer group average for all three periods. The Board
considered that the Fund's performance, relative to its performance peer group,
has improved, as the gap between the Fund's performance and the average of its
performance peer group has narrowed from the five- to the three- to the one-year
period. The Board also considered that the range of performance of all the funds
in the performance peer group is very narrow. The Board concluded that the
Fund's performance was improving and can reasonably be expected to be
competitive with that of its performance peer group.

FEES RELATIVE TO OTHER FUNDS MANAGED BY THE ADVISER WITH COMPARABLE INVESTMENT
STRATEGIES

The Board reviewed the advisory and administrative fees (together, the
"management fee") paid by the Fund under the Management Agreement. The Board
noted that the rate was comparable to the management fee rates charged by the
Adviser to any other funds it manages with investment strategies comparable to
those of the Fund.

                                        6
<Page>

FEES AND EXPENSES RELATIVE TO COMPARABLE FUNDS MANAGED BY OTHER ADVISERS

The Board reviewed the management fee rate and total expense ratio of the Fund.
The Board noted that: (i) the Fund's management fee rate was higher than the
average management fee rate for funds, selected by Lipper (the "expense peer
group"), managed by other advisers, with investment strategies comparable to
those of the Fund, as shown in the Lipper Report for this Fund; but (ii) the
Fund's total expense ratio was lower than the average total expense ratio of the
funds included in the Fund's expense peer group. The Board concluded that the
management fee rate was competitive in light of the fact that the Adviser
managed the Fund so that the total expense ratio of the Fund was less than the
total expense ratio of the funds in the expense peer group.

BREAKPOINTS AND ECONOMIES OF SCALE

The Board reviewed the structure of the Fund's management fee schedule under the
Management Agreement and noted that it includes breakpoints. The Board also
reviewed the level of the Fund's management fee and noted that the fee, as a
percentage of the Fund's net assets, would decrease as net assets increase
because the management fee includes breakpoints. The Board concluded that the
Fund's management fee would reflect economies of scale as assets increase.

PROFITABILITY OF ADVISER AND AFFILIATES

The Board considered and reviewed information concerning the costs incurred and
profits realized by the Adviser and its affiliates during the last two years
from their relationship with the Fund and the Morgan Stanley Fund Complex and
reviewed with the Controller of the Adviser the cost allocation methodology used
to determine the Adviser's profitability. Based on their review of the
information they received, the Board concluded that the profits earned by the
Adviser and its affiliates were not excessive in light of the advisory,
administrative and other services provided to the Fund.

FALL-OUT BENEFITS

The Board considered so-called "fall-out benefits" derived by the Adviser and
its affiliates from their relationship with the Fund and the Morgan Stanley Fund
Complex, such as "float" benefits derived from handling of checks for purchases
and redemptions of Fund shares through a broker-dealer affiliate of the Adviser.
The Board also considered that a broker-dealer affiliate of the Adviser receives
from the Fund 12b-1 fees for shareholder services. The Board concluded that the
float benefits were relatively small and that the 12b-1 fees were competitive
with those of other broker-dealer affiliates of investment advisers.

SOFT DOLLAR BENEFITS

The Board considered whether the Adviser realizes any benefits from commissions
paid to brokers who execute securities transactions for the Fund ("soft
dollars"). The Board noted that the Fund invests only in fixed income
securities, which do not generate soft dollars.

                                        7
<Page>

ADVISER FINANCIALLY SOUND AND FINANCIALLY CAPABLE OF MEETING THE FUND'S NEEDS

The Board considered whether the Adviser is financially sound and has the
resources necessary to perform its obligations under the Management Agreement.
The Board noted that the Adviser's operations remain profitable, although
increased expenses in recent years have reduced the Adviser's profitability. The
Board concluded that the Adviser has the financial resources necessary to
fulfill its obligations under the Management Agreement.

HISTORICAL RELATIONSHIP BETWEEN THE FUND AND THE ADVISER

The Board also reviewed and considered the historical relationship between the
Fund and the Adviser, including the organizational structure of the Adviser, the
policies and procedures formulated and adopted by the Adviser for managing the
Fund's operations and the Board's confidence in the competence and integrity of
the senior managers and key personnel of the Adviser. The Board concluded that
it is beneficial for the Fund to continue its relationship with the Adviser.

OTHER FACTORS AND CURRENT TRENDS

The Board considered the controls and procedures adopted and implemented by the
Adviser and monitored by the Fund's Chief Compliance Officer and concluded that
the conduct of business by the Adviser indicates a good faith effort on its part
to adhere to high ethical standards in the conduct of the Fund's business.

GENERAL CONCLUSION

After considering and weighing all of the above factors, the Board concluded it
would be in the best interest of the Fund and its shareholders to approve
renewal of the Management Agreement for another year.

                                        8
<Page>

ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST

PORTFOLIO OF INVESTMENTS - JUNE 30, 2005

<Table>
<Caption>
PRINCIPAL
AMOUNT IN                                                              COUPON         DEMAND
THOUSANDS                                                               RATE+          DATE*          VALUE
- ---------------------------------------------------------------------------------------------------------------
                                                                                      
              California Tax-Exempt Short-Term Variable Rate
              Municipal Obligations (87.6%)
              ABAG Finance Authority for Nonprofit Corporations,
$   8,000       Episcopal Homes Foundation Ser 2000 COPs                 2.38%        07/08/05    $   8,000,000
    5,000       Lease Purchase 2003 Ser A                                2.40         07/08/05        5,000,000
   13,980     Anaheim Public Finance Authority, Distribution
               System ROCs II-R Ser 6021 (MBIA)                          2.31         07/08/05       13,980,000
   20,000     Big Bear Lake, Southwest Gas Corp
               1993 Ser A (AMT)                                          2.28         07/08/05       20,000,000
    2,670     Cabrillo Community College District,
               2004 Ser A ROCs II-R 300 (MBIA)                           2.31         07/08/05        2,670,000
              California,
    2,400       Economic Recovery Ser 2004 C-3                           2.30         07/01/05        2,400,000
    3,000       Economic Recovery Ser 2004 C- 4                          2.22         07/01/05        3,000,000
    5,000       Economic Recovery Ser 2004 C-13 (XLCA)                   2.30         07/08/05        5,000,000
   15,700       Economic Recovery Ser 2004 C-18 (XLCA)                   2.50         07/08/05       15,700,000
    5,900       Economic Recovery Ser 2004 C-21 (XLCA)                   2.28         07/08/05        5,900,000
              California,
   10,020       Ser 2003 C-1                                             2.25         07/08/05       10,020,000
    6,300       Ser 2004 A-9                                             2.27         07/08/05        6,300,000
   36,200       Ser 2004 B-2                                             2.15         07/01/05       36,200,000
   11,970     California Alternative Energy Source Finance
               Authority, General Electric Capital Corp-Arroyo
                Energy 1993 Ser B (AMT)                                  2.25         07/08/05       11,970,000
              California Department of Water Resources,
    9,200       Power Supply Ser 2002 B Subser B-1                       2.22         07/01/05        9,200,000
    3,950       Power Supply Ser 2002 C-3                                2.25         07/08/05        3,950,000
   10,000       Power Supply Ser 2002 C Subser C-16                      2.27         07/08/05       10,000,000
    6,000       Power Supply Ser 2002 C Subser C-18                      2.25         07/08/05        6,000,000
              California Educational Facilities Authority,
    5,000       California Institute of Technology Ser 1994              2.25         07/08/05        5,000,000
    5,465       California Lutheran University Ser 2004 A                2.28         07/08/05        5,465,000
   15,165       Stanford University Ser L-5                              2.15         07/08/05       15,165,000
    7,000       University of San Francisco Ser 2003                     2.30         07/08/05        7,000,000
              California Health Facilities Financing Authority,
    6,900       Adventist Health System/West 1998
                 Ser A (MBIA) & B (MBIA)                                 2.22         07/01/05        6,900,000
   17,700       Northern California Presbyterian Homes &
                 Services Ser 2004                                       2.20         07/08/05       17,700,000
    1,000       Sisters of Charity of Leavenworth
                 Health System Ser 2003                                  2.30         07/08/05        1,000,000
</Table>

                        SEE NOTES TO FINANCIAL STATEMENTS

                                        9
<Page>

<Table>
<Caption>
PRINCIPAL
AMOUNT IN                                                              COUPON         DEMAND
THOUSANDS                                                               RATE+          DATE*          VALUE
- ---------------------------------------------------------------------------------------------------------------
                                                                                      
$   3,480     California Infrastructure & Economic Development
               Bank, Bay Area Toll Bridges Ser 2005 SGB-56 (Ambac).      2.31%        07/08/05    $   3,480,000
              California Statewide Communities Development Authority,
    6,000       Chabad of California Ser 2004                            2.23         07/08/05        6,000,000
    7,000       Coventry Place Apartments 2002 Ser JJ (AMT)              2.20         07/08/05        7,000,000
    4,200       Kaiser Permanente Ser 2004 L                             2.26         07/08/05        4,200,000
    8,240       Multifamily Housing Martin Luther Tower
                 2005 Ser D (AMT)                                        2.45         07/20/05        8,240,000
    3,500       University Retirement Community at Davis Inc
                 Ser 2003 (Radian)                                       2.23         07/01/05        3,500,000
   17,955     California Transit Finance Authority, Ser 1997 (FSA)       2.35         07/08/05       17,955,000
   15,000     East Bay Municipal Utility District, Wastewater
               Sub Ser 2005                                              2.23         07/08/05       15,000,000
    7,345     Fresno, Multifamily Housing Heron Pointe
               Apartments 2001 Ser A                                     2.22         07/08/05        7,345,000
   18,000     Fresno, Sewer System Sub Lien Ser 2000 A (FGIC)            2.20         07/08/05       18,000,000
              Irvine Assessment District,
    1,645       No 93-14 Improvement Bond Act 1915                       2.30         07/01/05        1,645,000
    2,750       No 03-19 Improvement Bond Act 1915 Ser A                 2.20         07/01/05        2,750,000
    9,745     Long Beach, Harbor PUTTERs Ser 444 (MBIA) (AMT)            2.31         07/08/05        9,745,000
   22,700     Los Angeles Community Redevelopment Agency,
               Grand Promenade Ser 2002                                  2.22         07/08/05       22,700,000
    6,000     Los Angeles County Metropolitan Transportation
               Authority, Prop C Sales Tax 2nd Ser 2004-A
               Eagle #20040046 (MBIA)                                    2.31         07/08/05        6,000,000
              Los Angeles Department of Water & Power,
    1,600       Power System 2001 Ser B Subser B-6                       2.21         07/01/05        1,600,000
    8,000       Power System 2002 Ser A Subser A-8                       2.27         07/08/05        8,000,000
    5,500       Water System 2001 Ser B Subser B-1                       2.25         07/08/05        5,500,000
   16,875     Los Angeles Housing Authority, Multi-Family 2004 Ser A     2.26         07/08/05       16,875,000
   11,000     Los Angeles Unified School District,
               P-FLOATs PT-1855 (FSA)                                    2.30         07/08/05       11,000,000
              Metropolitan Water District of Southern California,
    8,000       Water 1999 Ser C                                         2.25         07/08/05        8,000,000
   14,400       Waterworks 2002 Ser A                                    2.22         07/08/05       14,400,000
   15,100     Monterey Peninsula Water Management District,
               Wastewater Ser 1992 COPs                                  2.30         07/08/05       15,100,000
</Table>

                        SEE NOTES TO FINANCIAL STATEMENTS

                                       10
<Page>

<Table>
<Caption>
PRINCIPAL
AMOUNT IN                                                              COUPON         DEMAND
THOUSANDS                                                               RATE+          DATE*          VALUE
- ---------------------------------------------------------------------------------------------------------------
                                                                                      
$  13,300     Mountain View, Villa Mariposa Multifamily 1985 Ser A       2.29%        07/08/05    $  13,300,000
    5,655     Newport Beach, Hoag Memorial Hospital
               Presbyterian 1996 Ser B                                   2.23         07/01/05        5,655,000
    1,800     Orange County, Irvine Coast Assessment
               District No 88-1                                          2.22         07/01/05        1,800,000
    3,000     Orange County Housing Authority, Oasis
               Martinique Refg 1998 Issue I                              2.23         07/08/05        3,000,000
    2,075     Orange County Sanitation District, Ser 2000 B COPs         2.20         07/01/05        2,075,000
    7,000     Pasadena, City Hall & Park Improvement
               Ser 2003 COPs (Ambac)                                     2.27         07/08/05        7,000,000
   10,850     Pleasanton, Greenbriar Bernal Apartments
               Ser 2001 A (AMT)                                          2.24         07/08/05       10,850,000
    4,500     Pomona Redevelopment Agency, Park & Plaza
               Apartments Ser 1998 A                                     2.22         07/08/05        4,500,000
   14,600     Poway Unified School District, Ser 2004 COPs (FSA)         2.20         07/08/05       14,600,000
   13,200     Rancho Water District Financing Authority,
               Ser 2001 B (FGIC)                                         2.17         07/08/05       13,200,000
    6,750     Redlands, Orange Village Apartments 1988 Ser A (AMT)       2.35         07/08/05        6,750,000
    9,640     Riverside County, 2005 Ser A & B,
               COPs P-FLOATs PT-2704 (FGIC)                              2.30         07/08/05        9,640,000
    7,875     Roaring Fork Municipal Products, California
               Economic Recovery Class A Certificates
               Ser 2004-4 (FGIC)                                         2.26         07/08/05        7,875,000
    3,500     Sacramento County Housing Authority,
               Seasons at Winter 2004 Ser C-2                            2.20         07/08/05        3,500,000
    1,745     San Diego Unified School District, 1998
               Ser E-1 ROCs II-R Ser 1067 (MBIA)                         2.31         07/08/05        1,745,000
   11,275     San Francisco City & County, Folsom-Dore
               Apartments Ser 2002 A (AMT)                               2.59         07/08/05       11,275,000
              San Francisco City & County Redevelopment Agency,
   21,000       Bayside Village Multifamily Ser 1985 A                   2.24         07/08/05       21,000,000
    6,000       Mercy Terrace Ser 2005 A                                 2.20         07/08/05        6,000,000
    2,000     San Jose, Multifamily Almaden Lake Village
               Apartments Ser 2000 A (AMT)                               2.30         07/08/05        2,000,000
   12,400     Santa Clara, Multifamily Briarwood Apartments
               Ser 1996 B                                                2.20         07/08/05       12,400,000
</Table>

                        SEE NOTES TO FINANCIAL STATEMENTS

                                       11
<Page>

<Table>
<Caption>
PRINCIPAL
AMOUNT IN                                                              COUPON         DEMAND
THOUSANDS                                                               RATE+          DATE*          VALUE
- ---------------------------------------------------------------------------------------------------------------
                                                                                      
 $  4,705     Turlock Irrigation District, Ser 1988 A                    2.30%        07/08/05    $   4,705,000
    6,165     Ventura County, 2003 COPs PUTTERs
               Ser 474 (FSA)                                             2.31         07/08/05        6,165,000
                                                                                                  -------------
              Total California Tax-Exempt Short-Term Variable Rate
               Municipal Obligations
               (COST $616,590,000)                                                                  616,590,000
                                                                                                  -------------

<Caption>
                                                                                     YIELD TO
                                                                                     MATURITY
                                                                COUPON   MATURITY   ON DATE OF
                                                                 RATE      DATE      PURCHASE
                                                                ------   ---------  ----------
                                                                                      
              California Tax-Exempt Commercial Paper (10.1%)
    1,809     California Department of
               Water Resources, Ser 1                             2.78%   07/19/05        2.78%       1,809,000
              California Infrastructure & Economic
               Development Bank,
    3,300       Bay Area Toll Seismic Retrofit Ser 2005           2.37    07/21/05        2.37        3,300,000
    6,000       Bay Area Toll Seismic Retrofit Ser 2005           2.35    08/04/05        2.35        6,000,000
   10,000     California Statewide Communities Development
               Authority, Kaiser Permanente Ser 2004 K            2.82    07/14/05        2.82       10,000,000
    4,400     San Diego County Regional Airport Authority,
               Lindberg Field Ser B                               2.50    10/06/05        2.50        4,400,000
   10,000     San Diego County Water Authority, Ser 1             2.73    08/29/05        2.73       10,000,000
   10,000     San Francisco City & County Public
               Utilities Commission, Water Ser 2001               2.68    07/26/05        2.68       10,000,000
    4,000     San Francisco County Transportation Authority,
               2004 Ser A                                         2.40    07/21/05        2.40        4,000,000
              San Gabriel Valley Council of Governments,
    6,400       Alameda Corridor-East GANs                        2.37    07/12/05        2.37        6,400,000
   15,000       Alameda Corridor-East GANs                        2.45    07/12/05        2.45       15,000,000
                                                                                                  -------------
              Total California Tax-Exempt Commercial Paper
               (COST $70,909,000)                                                                    70,909,000
                                                                                                  -------------

              California Tax-Exempt Short-Term Municipal Notes
               (8.1%)
              California School Cash Reserve Program Authority,
   19,000       2004 Pool Ser A, dtd 07/06/04                     3.00    07/06/05        1.60       19,003,584
    6,000       2005 Pool Ser A, dtd 07/06/05 (WI)                4.00    07/06/06        2.60        6,081,840
    1,950     Mt Diablo Unified School District,
               Ser 2004 TRANs, dtd 11/10/04                       3.00    11/09/05        2.20        1,955,387
    3,700     Placentia, Ser 2005 TRANs, dtd 07/01/05 (WI)        3.75    06/30/06        2.80        3,734,077
</Table>

                        SEE NOTES TO FINANCIAL STATEMENTS

                                       12
<Page>

<Table>
<Caption>
                                                                                     YIELD TO
PRINCIPAL                                                                            MATURITY
AMOUNT IN                                                       COUPON   MATURITY   ON DATE OF
THOUSANDS                                                        RATE      DATE      PURCHASE         VALUE
- ---------------------------------------------------------------------------------------------------------------
                                                                                   
$  13,000     Sacramento County, 2004 Ser A TRANs,
               dtd 07/01/04                                       3.00%   07/11/05        1.65%   $  13,004,729
    7,000     Santa Cruz County, 2004-2005 A TRANs,
               dtd 07/07/04                                       3.00    07/06/05        1.62        7,001,302
    1,750     Selma, Ser 2005 TRANs, dtd 07/01/05 (WI)            4.00    06/30/06        2.80        1,770,370
    4,750     Victor Valley Joint Union High School District,
               Ser 2004 TRANs, dtd 07/22/04                       2.75    07/21/05        1.65        4,752,816
                                                                                                  -------------
              Total California Tax-Exempt Short-Term Municipal
               Notes (COST $57,304,105)                                                              57,304,105
                                                                                                  -------------
              Total Investments (COST $744,803,105) (a) (b)                              105.8%     744,803,105

              Liabilities In Excess of Other Assets                                       (5.8)     (40,512,003)
                                                                                         -----    -------------
              Net Assets                                                                 100.0%   $ 704,291,102
                                                                                         =====    =============
</Table>

- ----------
    AMT    ALTERNATIVE MINIMUM TAX.
   COPS    CERTIFICATES OF PARTICIPATION.
   GANS    GRANT ANTICIPATION NOTES.
 P-FLOATS  PUTTABLE FLOATING OPTION TAX-EXEMPT RECEIPTS.
  PUTTERS  PUTTABLE TAX-EXEMPT RECEIPTS.
   ROCS    RESET OPTION CERTIFICATES.
   TRANS   TAX AND REVENUE ANTICIPATION NOTES.
    WI     SECURITY PURCHASED ON A WHEN-ISSUED BASIS.
    +      RATE SHOWN IS THE RATE IN EFFECT AT JUNE 30, 2005.
    *      DATE ON WHICH THE PRINCIPAL AMOUNT CAN BE RECOVERED THROUGH DEMAND.
   (a)     SECURITIES HAVE BEEN DESIGNATED AS COLLATERAL IN AN AMOUNT EQUAL TO
           $11,586,287 IN CONNECTION WITH THE PURCHASE OF WHEN-ISSUED
           SECURITIES.
   (b)     COST IS THE SAME FOR FEDERAL INCOME TAX PURPOSES.

BOND INSURANCE:
   AMBAC   AMBAC ASSURANCE CORPORATION.
   FGIC    FINANCIAL GUARANTY INSURANCE COMPANY.
    FSA    FINANCIAL SECURITY ASSURANCE INC.
   MBIA    MUNICIPAL BOND INVESTORS ASSURANCE CORPORATION.
  RADIAN   RADIAN ASSET ASSURANCE INC.
   XLCA    XL CAPITAL ASSURANCE INC.

                        SEE NOTES TO FINANCIAL STATEMENTS

                                       13
<Page>

ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST

FINANCIAL STATEMENTS

STATEMENT OF ASSETS AND LIABILITIES
JUNE 30, 2005

<Table>
                                                                                        
ASSETS:
Investments in securities, at value (cost $744,803,105)                                    $   744,803,105
Cash                                                                                                80,041
Interest receivable                                                                              3,144,702
Prepaid expenses and other assets                                                                   29,333
                                                                                           ---------------
    TOTAL ASSETS                                                                               748,057,181
                                                                                           ---------------
LIABILITIES:
Payable for:
    Investments purchased                                                                       43,314,824
    Investment advisory fee                                                                        255,025
    Distribution fee                                                                                59,788
    Administration fee                                                                              29,894
Accrued expenses and other payables                                                                106,548
                                                                                           ---------------
    TOTAL LIABILITIES                                                                           43,766,079
                                                                                           ---------------
    NET ASSETS                                                                             $   704,291,102
                                                                                           ===============
COMPOSITION OF NET ASSETS:
Paid-in-capital                                                                            $   704,286,145
Accumulated undistributed net investment income                                                      4,957
                                                                                           ---------------
    NET ASSETS                                                                             $   704,291,102
                                                                                           ===============
NET ASSET VALUE PER SHARE,
704,266,819 shares outstanding (unlimited shares authorized of $.01 par value)             $          1.00
                                                                                           ===============
</Table>

                        SEE NOTES TO FINANCIAL STATEMENTS

                                       14
<Page>

STATEMENT OF OPERATIONS
FOR THE YEAR ENDED JUNE 30, 2005

<Table>
                                                                                        
NET INVESTMENT INCOME:

INTEREST INCOME                                                                            $    12,596,959
                                                                                           ---------------
EXPENSES
Investment advisory fee                                                                          3,157,024
Distribution fee                                                                                   709,565
Administration fee                                                                                 233,626
Transfer agent fees and expenses                                                                    96,554
Professional fees                                                                                   64,515
Shareholder reports and notices                                                                     34,213
Custodian fees                                                                                      34,118
Trustees' fees and expenses                                                                         15,565
Registration fees                                                                                   14,280
Other                                                                                               36,536
                                                                                           ---------------
    TOTAL EXPENSES                                                                               4,395,996

LESS: EXPENSE OFFSET                                                                               (33,362)
                                                                                           ---------------
    NET EXPENSES                                                                                 4,362,634
                                                                                           ---------------
NET INVESTMENT INCOME                                                                      $     8,234,325
                                                                                           ===============
</Table>

                        SEE NOTES TO FINANCIAL STATEMENTS

                                       15
<Page>

STATEMENT OF CHANGES IN NET ASSETS

<Table>
<Caption>
                                                                                FOR THE YEAR    FOR THE YEAR
                                                                                   ENDED           ENDED
                                                                               JUNE 30, 2005   JUNE 30, 2004
                                                                               -------------   -------------
                                                                                         
INCREASE (DECREASE) IN NET ASSETS:

OPERATIONS:

Net investment income                                                          $   8,234,325   $   2,590,346

Dividends to shareholders from net investment income                              (8,234,061)     (2,590,218)

Net increase (decrease) from transactions in shares of beneficial interest        16,490,532     (74,647,531)
                                                                               -------------   -------------

    NET INCREASE (DECREASE)                                                       16,490,796     (74,647,403)

NET ASSETS:
Beginning of period                                                              687,800,306     762,447,709
                                                                               -------------   -------------

END OF PERIOD
(INCLUDING ACCUMULATED UNDISTRIBUTED NET INVESTMENT INCOME OF
$4,957 AND $4,693, RESPECTIVELY)                                               $ 704,291,102   $ 687,800,306
                                                                               =============   =============
</Table>

                        SEE NOTES TO FINANCIAL STATEMENTS

                                       16
<Page>

ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST

NOTES TO FINANCIAL STATEMENTS - JUNE 30, 2005

1. ORGANIZATION AND ACCOUNTING POLICIES
Active Assets California Tax-Free Trust (the "Fund") is registered under the
Investment Company Act of 1940, as amended (the "Act"), as a diversified,
open-end management investment company. The Fund's investment objective is to
provide a high level of daily income which is exempt from federal and California
income tax consistent with stability of principal and liquidity. The Fund was
organized as a Massachusetts business trust on July 10, 1991 and commenced
operations on November 12, 1991.

The following is a summary of significant accounting policies:

A. VALUATION OF INVESTMENTS -- Portfolio securities are valued at amortized
cost, which approximates market value.

B. ACCOUNTING FOR INVESTMENTS -- Security transactions are accounted for on the
trade date (date the order to buy or sell is executed). Realized gains and
losses on security transactions are determined by the identified cost method.
Discounts are accreted and premiums are amortized over the life of the
respective securities. Interest income is accrued daily.

C. FEDERAL INCOME TAX POLICY -- It is the Fund's policy to comply with the
requirements of the Internal Revenue Code applicable to regulated investment
companies and to distribute substantially all of its taxable and nontaxable
income to its shareholders. Accordingly, no federal income tax provision is
required.

D. DIVIDENDS AND DISTRIBUTIONS TO SHAREHOLDERS -- The Fund records dividends and
distributions to shareholders as of the close of each business day.

E. USE OF ESTIMATES -- The preparation of financial statements in accordance
with generally accepted accounting principles requires management to make
estimates and assumptions that affect the reported amounts and disclosures.
Actual results could differ from those estimates.

2. INVESTMENT ADVISORY/ADMINISTRATION AGREEMENTS
Effective November 1, 2004, pursuant to an Investment Advisory Agreement with
Morgan Stanley Investment Advisors Inc. (the "Investment Adviser"), the Fund
pays the Investment Adviser an advisory fee, accrued daily and payable monthly,
by applying the following annual rates to the net assets of the Fund determined
as of the close of each business day: 0.45% to the portion of the daily net
assets not exceeding $500 million; 0.375% to the portion of the daily net assets
exceeding $500 million but not exceeding $750 million; 0.325% to the portion of
the daily net assets exceeding $750 million but not exceeding $1 billion; 0.30%
to the portion of the daily net assets exceeding $1 billion but not exceeding
$1.5 billion; 0.275% to the portion of the daily net assets exceeding $1.5
billion but not exceeding $2 billion; 0.25% to the portion of the daily net
assets exceeding $2 billion but not exceeding $2.5 billion; 0.225% to the
portion of the daily net assets exceeding $2.5 billion but not exceeding $3
billion; and 0.20% to the portion of the daily net assets exceeding $3 billion.

                                       17
<Page>

Effective November 1, 2004, pursuant to Administration Agreement with Morgan
Stanley Services Company Inc. (the "Administrator"), an affiliate of the
Investment Adviser, the Fund pays an administration fee, accrued daily and
payable monthly, by applying the annual rate of 0.05% to the Fund's daily net
assets.

Prior to November 1, 2004, the Fund had retained the Investment Adviser to
provide administrative services and to manage the investment of the Fund's
assets pursuant to an investment management agreement pursuant to which the Fund
paid the Investment Adviser a monthly management fee, accrued daily and payable
monthly, by applying the annual rates to the net assets of the Fund determined
as of the close of each business day: 0.50% to the portion of the daily net
assets not exceeding $500 million; 0.425% to the portion of the daily net assets
exceeding $500 million but not exceeding $750 million; 0.375% to the portion of
the daily net assets exceeding $750 million but not exceeding $1 billion; 0.35%
to the portion of the daily net assets exceeding $1 billion but not exceeding
$1.5 billion; 0.325% to the portion of the daily net assets exceeding $1.5
billion but not exceeding $2 billion; 0.30% to the portion of the daily net
assets exceeding $2 billion but not exceeding $2.5 billion; 0.275% to the
portion of the daily net assets exceeding $2.5 billion but not exceeding $3
billion; and 0.25% to the portion of the daily net assets exceeding $3 billion.

3. PLAN OF DISTRIBUTION
Morgan Stanley Distributors Inc. (the "Distributor"), an affiliate of the
Investment Adviser and Administrator, is the distributor of the Fund's shares
and in accordance with a Plan of Distribution (the "Plan") pursuant to
Rule 12b-1 under the Act, finances certain expenses in connection with the
promotion of sales of Fund shares.

Reimbursements for these expenses are made in monthly payments by the Fund to
the Distributor, which will in no event exceed an amount equal to a payment at
the annual rate of 0.15% of the Fund's average daily net assets during the
month. Expenses incurred by the Distributor pursuant to the Plan in any fiscal
year will not be reimbursed by the Fund through payments accrued in any
subsequent fiscal year. For the year ended June 30, 2005, the distribution fee
was accrued at the annual rate of 0.10%.

4. SECURITY TRANSACTIONS AND TRANSACTIONS WITH AFFILIATES
The cost of purchases and proceeds from sales/maturities of portfolio securities
for the year ended June 30, 2005, aggregated $1,917,675,208 and $1,930,202,000,
respectively.

Morgan Stanley Trust, an affiliate of the Investment Adviser, Administrator and
Distributor, is the Fund's transfer agent.

                                       18
<Page>

The Fund has an unfunded noncontributory defined benefit pension plan covering
certain independent Trustees of the Fund who will have served as independent
Trustees for at least five years at the time of retirement. Benefits under this
plan are based on factors which include years of service and compensation.
Aggregate pension costs for the year ended June 30, 2005, included in Trustees'
fees and expenses in the Statement of Operations amounted to $6,588. At June 30,
2005, the Fund had an accrued pension liability of $55,006 which is included in
accrued expenses in the Statement of Assets and Liabilities. On December 2,
2003, the Trustees voted to close the plan to new participants and eliminate the
future benefits growth due to increases to compensation after July 31, 2003.

The Fund has an unfunded Deferred Compensation Plan (the "Compensation Plan")
which allows each independent Trustee to defer payment of all, or a portion, of
the fees he receives for serving on the Board of Trustees. Each eligible Trustee
generally may elect to have the deferred amounts credited with a return equal to
the total return on one or more of the Morgan Stanley funds that are offered as
investment options under the Compensation Plan. Appreciation/depreciation and
distributions received from these investments are recorded with an offsetting
increase/decrease in the deferred compensation obligation and do not affect the
net asset value of the Fund.

5. SHARES OF BENEFICIAL INTEREST
Transactions in shares of beneficial interest, at $1.00 per share, were as
follows:

<Table>
<Caption>
                                                                         FOR THE YEAR      FOR THE YEAR
                                                                             ENDED             ENDED
                                                                         JUNE 30, 2005     JUNE 30, 2004
                                                                        --------------    --------------
                                                                                    
Shares sold                                                              2,680,347,592     2,395,182,645
Shares issued in reinvestment of dividends                                   8,234,061         2,590,218
                                                                        --------------    --------------
                                                                         2,688,581,653     2,397,772,863
Shares redeemed                                                         (2,672,091,121)   (2,472,420,394)
                                                                        --------------    --------------
Net increase (decrease) in shares outstanding                               16,490,532       (74,647,531)
                                                                        ==============    ==============
</Table>

6. EXPENSE OFFSET
The expense offset represents a reduction of the custodian fees for earnings on
cash balances maintained by the Fund.

7. LEGAL MATTERS
The Investment Adviser, certain affiliates of the Investment Adviser, certain
officers of such affiliates and certain investment companies advised by the
Investment Adviser or its affiliates, including the Fund, are named as
defendants in a consolidated class action. This consolidated action also names
as defendants certain individual Trustees and Directors of the Morgan Stanley
funds. The consolidated amended complaint generally alleges that defendants,
including the Fund, violated their statutory

                                       19
<Page>

disclosure obligations and fiduciary duties by failing properly to disclose (i)
that the Investment Adviser and certain affiliates of the Investment Adviser
allegedly offered economic incentives to brokers and others to recommend the
funds advised by the Investment Adviser or its affiliates to investors rather
than funds managed by other companies, and (ii) that the funds advised by the
Investment Adviser or its affiliates, including the Fund, allegedly paid
excessive commissions to brokers in return for their efforts to recommend these
funds to investors. The complaint seeks, among other things, unspecified
compensatory damages, rescissionary damages, fees and costs. The defendants have
moved to dismiss the action and intend to otherwise vigorously defend it. On
March 10, 2005, Plaintiffs sought leave to supplement their complaint to assert
claims on behalf of other investors. While the Fund and Adviser believe that
each has meritorious defenses, the ultimate outcome of this matter is not
presently determinable at this early stage of the litigation, and no provision
has been made in the Fund's financial statements for the effect, if any, of this
matter.

                                       20
<Page>

ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST

FINANCIAL HIGHLIGHTS

Selected ratios and per share data for a share of beneficial interest
outstanding throughout each period:

<Table>
<Caption>
                                                                        FOR THE YEAR ENDED JUNE 30,
                                            -----------------------------------------------------------------------------------
                                                2005                2004             2003             2002             2001
                                            ------------        ------------     ------------     ------------     ------------
                                                                                                    
SELECTED PER SHARE DATA:
Net asset value, beginning of period        $       1.00        $       1.00     $       1.00     $       1.00     $       1.00
                                            ------------        ------------     ------------     ------------     ------------
Net income from investment operations              0.012               0.003            0.006            0.011            0.026
Less dividends from net investment income         (0.012)             (0.003)          (0.006)          (0.011)          (0.026)
                                            ------------        ------------     ------------     ------------     ------------
Net asset value, end of period              $       1.00        $       1.00     $       1.00     $       1.00     $       1.00
                                            ============        ============     ============     ============     ============
TOTAL RETURN                                        1.17%               0.35%            0.63%            1.15%            2.68%

RATIOS TO AVERAGE NET ASSETS:
Expenses (before expense offset)                    0.62%(1)            0.61%            0.60%            0.60%            0.59%
Net investment income                               1.16%               0.35%            0.63%            1.14%            2.64%

SUPPLEMENTAL DATA:
Net assets, end of period, in thousands     $    704,291        $    687,800     $    762,448     $    762,656     $    759,089
</Table>

- ----------
(1)  DOES NOT REFLECT THE EFFECT OF EXPENSE OFFSET OF 0.01%.

                        SEE NOTES TO FINANCIAL STATEMENTS

                                       21
<Page>

ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

TO THE SHAREHOLDERS AND BOARD OF TRUSTEES
OF ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST:

We have audited the accompanying statement of assets and liabilities of Active
Assets California Tax-Free Trust (the "Fund"), including the portfolio of
investments, as of June 30, 2005, and the related statements of operations for
the year then ended and changes in net assets for each of the two years in the
period then ended, and the financial highlights for each of the five years in
the period then ended. These financial statements and financial highlights are
the responsibility of the Fund's management. Our responsibility is to express an
opinion on these financial statements and financial highlights based on our
audits.

We conducted our audits in accordance with the standards of the Public Company
Accounting Oversight Board (United States). Those standards require that we plan
and perform the audit to obtain reasonable assurance about whether the financial
statements and financial highlights are free of material misstatement. The Fund
is not required to have, nor were we engaged to perform, an audit of its
internal control over financial reporting. Our audits included consideration of
internal control over financial reporting as a basis for designing audit
procedures that are appropriate in the circumstances, but not for the purpose of
expressing an opinion on the effectiveness of the Fund's internal control over
financial reporting. Accordingly, we express no such opinion. An audit also
includes examining, on a test basis, evidence supporting the amounts and
disclosures in the financial statements, assessing the accounting principles
used and significant estimates made by management, as well as evaluating the
overall financial statement presentation. Our procedures included confirmation
of securities owned as of June 30, 2005, by correspondence with the custodian
and brokers. We believe that our audits provide a reasonable basis for our
opinion.

In our opinion, the financial statements and financial highlights referred to
above present fairly, in all material respects, the financial position of Active
Assets California Tax-Free Trust as of June 30, 2005, the results of its
operations for the year then ended, the changes in its net assets for each of
the two years in the period then ended, and the financial highlights for each of
the five years in the period then ended, in conformity with accounting
principles generally accepted in the United States of America.

Deloitte & Touche LLP
NEW YORK, NEW YORK
AUGUST 15, 2005

                                       22
<Page>

ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST

TRUSTEE AND OFFICER INFORMATION

INDEPENDENT TRUSTEES:

<Table>
<Caption>
                                                                                               NUMBER OF
                                                                                              PORTFOLIOS
                                                        TERM OF                                 IN FUND
                                         POSITION(S)   OFFICE AND                               COMPLEX
       NAME, AGE AND ADDRESS OF           HELD WITH    LENGTH OF    PRINCIPAL OCCUPATION(S)    OVERSEEN       OTHER DIRECTORSHIPS
         INDEPENDENT TRUSTEE             REGISTRANT   TIME SERVED*   DURING PAST 5 YEARS**   BY TRUSTEE***      HELD BY TRUSTEE
- ---------------------------------------  -----------  ------------  -----------------------  -------------  -----------------------
                                                                                             
Michael Bozic (64)                       Trustee      Since         Private Investor;        197            Director of various
c/o Kramer Levin Naftalis & Frankel LLP               April 1994    Director or Trustee of                  business organizations.
Counsel to the Independent Trustees                                 the Retail Funds (since
1177 Avenue of the Americas                                         April 1994) and the
New York, NY 10036                                                  Institutional Funds
                                                                    (since July 2003);
                                                                    formerly Vice Chairman
                                                                    of Kmart Corporation
                                                                    (December 1998-
                                                                    October 2000), Chairman
                                                                    and Chief Executive
                                                                    Officer of Levitz
                                                                    Furniture Corporation
                                                                    (November 1995-
                                                                    November 1998) and
                                                                    President and Chief
                                                                    Executive Officer of
                                                                    Hills Department Stores
                                                                    (May 1991- July 1995);
                                                                    formerly variously
                                                                    Chairman, Chief
                                                                    Executive Officer,
                                                                    President and Chief
                                                                    Operating Officer
                                                                    (1987-1991) of the
                                                                    Sears Merchandise Group
                                                                    of Sears, Roebuck & Co.

Edwin J. Garn (72)                       Trustee      Since         Consultant; Director or  197            Director of Franklin
1031 N. Chartwell Court                               January 1993  Trustee of the Retail                   Covey (time management
Salt Lake City, UT 84103                                            Funds (since                            systems), BMW Bank of
                                                                    January 1993) and the                   North America, Inc.
                                                                    Institutional Funds                     (industrial loan
                                                                    (since July 2003);                      corporation), Escrow
                                                                    member of the Utah                      Bank USA (industrial
                                                                    Regional Advisory Board                 loan corporation),
                                                                    of Pacific Corp.                        United Space Alliance
                                                                    (Utility Company);                      (joint venture between
                                                                    formerly Managing                       Lockheed Martin and the
                                                                    Director of Summit                      Boeing Company) and
                                                                    Ventures LLC                            Nuskin Asia Pacific
                                                                    (Lobbying and Consulting                (multilevel marketing);
                                                                    Firm) (2000-2004);                      member of the board of
                                                                    United States Senator                   various civic and
                                                                    (R-Utah) (1974-1992)                    charitable
                                                                    and Chairman, Senate                    organizations.
                                                                    Banking Committee
                                                                    (1980-1986), Mayor of
                                                                    Salt Lake City, Utah
                                                                    (1971-1974), Astronaut,
                                                                    Space Shuttle Discovery
                                                                    (April 12-19, 1985), and
                                                                    Vice Chairman, Huntsman
                                                                    Corporation (chemical
                                                                    company).

Wayne E. Hedien (71)                     Trustee      Since         Retired; Director or     197            Director of The PMI
c/o Kramer Levin Naftalis & Frankel LLP               September     Trustee of the Retail                   Group Inc. (private
Counsel to the Independent Trustees                   1997          Funds (since                            mortgage insurance);
1177 Avenue of the Americas                                         September 1997) and the                 Trustee and Vice
New York, NY 10036                                                  Institutional Funds                     Chairman of The Field
                                                                    (since July 2003);                      Museum of Natural
                                                                    formerly associated                     History; director of
                                                                    with the Allstate                       various other business
                                                                    Companies (1966-1994),                  and charitable
                                                                    most recently as                        organizations.
                                                                    Chairman of The
                                                                    Allstate Corporation
                                                                    (March 1993-
                                                                    December 1994) and
                                                                    Chairman and Chief
                                                                    Executive Officer of
                                                                    its wholly-owned
                                                                    subsidiary, Allstate
                                                                    Insurance Company
                                                                    (July 1989-December
                                                                    1994).
</Table>

                                       23
<Page>

<Table>
<Caption>
                                                                                               NUMBER OF
                                                                                              PORTFOLIOS
                                                        TERM OF                                IN FUND
                                         POSITION(S)   OFFICE AND                              COMPLEX
       NAME, AGE AND ADDRESS OF           HELD WITH    LENGTH OF    PRINCIPAL OCCUPATION(S)    OVERSEEN       OTHER DIRECTORSHIPS
         INDEPENDENT TRUSTEE             REGISTRANT   TIME SERVED*   DURING PAST 5 YEARS**   BY TRUSTEE***      HELD BY TRUSTEE
- ---------------------------------------  -----------  ------------  -----------------------  -------------  -----------------------
                                                                                             
Dr. Manuel H. Johnson (56)               Trustee      Since         Senior Partner, Johnson  197            Director of NVR, Inc.
c/o Johnson Smick Group, Inc.                         July 1991     Smick International,                    (home construction);
888 16th Street, NW                                                 Inc., a consulting                      Director of KFX Energy;
Suite 740                                                           firm; Chairman of the                   Director of RBS
Washington, D.C. 20006                                              Audit Committee and                     Greenwich Capital
                                                                    Director or Trustee of                  Holdings (financial
                                                                    the Retail Funds (since                 holding company).
                                                                    July 1991) and the
                                                                    Institutional Funds
                                                                    (since July 2003);
                                                                    Co-Chairman and a
                                                                    founder of the Group of
                                                                    Seven Council (G7C), an
                                                                    international economic
                                                                    commission; formerly
                                                                    Vice Chairman of the
                                                                    Board of Governors of
                                                                    the Federal Reserve
                                                                    System and Assistant
                                                                    Secretary of the U.S.
                                                                    Treasury.

Joseph J. Kearns (62)                    Trustee      Since         President, Kearns &      198            Director of Electro
c/o Kearns & Associates LLC                           July 2003     Associates LLC                          Rent Corporation
PMB754                                                              (investment                             (equipment leasing),
23852 Pacific Coast Highway                                         consulting); Deputy                     The Ford Family
Malibu, CA 90265                                                    Chairman of the Audit                   Foundation, and the
                                                                    Committee and Director                  UCLA Foundation.
                                                                    or Trustee of the
                                                                    Retail Funds (since
                                                                    July 2003) and the
                                                                    Institutional Funds
                                                                    (since August 1994);
                                                                    previously Chairman of
                                                                    the Audit Committee of
                                                                    the Institutional Funds
                                                                    (October 2001-July
                                                                    2003); formerly CFO of
                                                                    the J. Paul Getty Trust.

Michael E. Nugent (69)                   Trustee      Since         General Partner of       197            Director of various
c/o Triumph Capital, L.P.                             July 1991     Triumph Capital, L.P.,                  business organizations.
445 Park Avenue                                                     a private investment
New York, NY 10022                                                  partnership; Chairman
                                                                    of the Insurance
                                                                    Committee and Director
                                                                    or Trustee of the
                                                                    Retail Funds (since
                                                                    July 1991) and the
                                                                    Institutional Funds
                                                                    (since July 2001);
                                                                    formerly Vice
                                                                    President, Bankers
                                                                    Trust Company and BT
                                                                    Capital Corporation
                                                                    (1984-1988).

Fergus Reid (72)                         Trustee      Since         Chairman of Lumelite     198            Trustee and Director of
c/o Lumelite Plastics Corporation                     July 2003     Plastics Corporation;                   certain investment
85 Charles Colman Blvd.                                             Chairman of the                         companies in the
Pawling, NY 12564                                                   Governance Committee                    JPMorgan Funds complex
                                                                    and Director or Trustee                 managed by J.P. Morgan
                                                                    of the Retail Funds                     Investment Management
                                                                    (since July 2003) and                   Inc.
                                                                    the Institutional Funds
                                                                    (since June 1992).
</Table>

                                       24
<Page>

INTERESTED TRUSTEES:

<Table>
<Caption>
                                                                                               NUMBER OF
                                                                                              PORTFOLIOS
                                                        TERM OF                                IN FUND
                                         POSITION(S)   OFFICE AND                              COMPLEX
       NAME, AGE AND ADDRESS OF           HELD WITH    LENGTH OF    PRINCIPAL OCCUPATION(S)    OVERSEEN       OTHER DIRECTORSHIPS
          INTERESTED TRUSTEE             REGISTRANT   TIME SERVED*   DURING PAST 5 YEARS**   BY TRUSTEE***      HELD BY TRUSTEE
- ---------------------------------------  -----------  ------------  -----------------------  -------------  -----------------------
                                                                                             
Charles A. Fiumefreddo (72)              Chairman of  Since         Chairman and Director    197            None.
c/o Morgan Stanley Trust                 the Board    July 1991     or Trustee of the
Harborside Financial Center,             and Trustee                Retail Funds (since
Plaza Two,                                                          July 1991) and the
Jersey City, NJ 07311                                               Institutional Funds
                                                                    (since July 2003);
                                                                    formerly Chief
                                                                    Executive Officer of
                                                                    the Retail Funds (until
                                                                    September 2002).

James F. Higgins (57)                    Trustee      Since         Director or Trustee of   197            Director of AXA
c/o Morgan Stanley Trust                              June 2000     the Retail Funds (since                 Financial, Inc. and The
Harborside Financial Center,                                        June 2000) and the                      Equitable Life Assurance
Plaza Two,                                                          Institutional Funds                     Society of the United
Jersey City, NJ 07311                                               (since July 2003);                      States (financial
                                                                    Senior Advisor of                       services).
                                                                    Morgan Stanley (since
                                                                    August 2000); Director
                                                                    of the Distributor and
                                                                    Dean Witter Realty
                                                                    Inc.; previously
                                                                    President and Chief
                                                                    Operating Officer of
                                                                    the Private Client
                                                                    Group of Morgan Stanley
                                                                    (May 1999-August 2000),
                                                                    and President and Chief
                                                                    Operating Officer of
                                                                    Individual Securities
                                                                    of Morgan Stanley
                                                                    (February 1997-May
                                                                    1999).
</Table>

- ----------
   * THIS IS THE EARLIEST DATE THE TRUSTEE BEGAN SERVING THE FUNDS ADVISED BY
     MORGAN STANLEY INVESTMENT ADVISORS INC. (THE "INVESTMENT ADVISER ") (THE
     "RETAIL FUNDS ").
  ** THE DATES REFERENCED BELOW INDICATING COMMENCEMENT OF SERVICES AS
     DIRECTOR/TRUSTEE FOR THE RETAIL FUNDS AND THE FUNDS ADVISED BY MORGAN
     STANLEY INVESTMENT MANAGEMENT INC. AND MORGAN STANLEY AIP GP LP (THE
     "INSTITUTIONAL FUNDS") REFLECT THE EARLIEST DATE THE DIRECTOR/TRUSTEE BEGAN
     SERVING THE RETAIL OR INSTITUTIONAL FUNDS, AS APPLICABLE.
 *** THE FUND COMPLEX INCLUDES ALL OPEN-END AND CLOSED-END FUNDS (INCLUDING ALL
     OF THEIR PORTFOLIOS) ADVISED BY THE INVESTMENT ADVISER AND ANY FUNDS THAT
     HAVE AN INVESTMENT ADVISER THAT IS AN AFFILIATED PERSON OF THE INVESTMENT
     ADVISER (INCLUDING, BUT NOT LIMITED TO, MORGAN STANLEY INVESTMENT
     MANAGEMENT INC.).

                                       25
<Page>

OFFICERS:

<Table>
<Caption>
                                                    TERM OF
                                 POSITION(S)      OFFICE AND
  NAME, AGE AND ADDRESS OF        HELD WITH        LENGTH OF
     EXECUTIVE OFFICER           REGISTRANT      TIME SERVED*            PRINCIPAL OCCUPATION(S) DURING PAST 5 YEARS**
- ----------------------------   ---------------  ---------------   ------------------------------------------------------------
                                                         
Mitchell M. Merin (51)         President        Since May 1999    President and Chief Operating Officer of Morgan Stanley
1221 Avenue of the Americas                                       Investment Management Inc.; President, Director and Chief
New York, NY 10020                                                Executive Officer of the Investment Adviser and the
                                                                  Administrator; Chairman and Director of the Distributor;
                                                                  Chairman and Director of the Transfer Agent; Director of
                                                                  various Morgan Stanley subsidiaries; President of the
                                                                  Institutional Funds (since July 2003) and President of the
                                                                  Retail Funds (since May 1999); Trustee (since July 2003) and
                                                                  President (since December 2002) of the Van Kampen Closed-End
                                                                  Funds; Trustee and President (since October 2002) of the Van
                                                                  Kampen Open-End Funds.

Ronald E. Robison (66)         Executive Vice   Since             Principal Executive Officer of Funds in the Fund Complex
1221 Avenue of the Americas    President and    April 2003        (since May 2003); Managing Director of Morgan Stanley & Co.
New York, NY 10020             Principal                          Incorporated, Morgan Stanley Investment Management Inc. and
                               Executive                          Morgan Stanley; Managing Director, Chief Administrative
                               Officer                            Officer and Director of the Investment Adviser and the
                                                                  Administrator; Director of the Transfer Agent; Managing
                                                                  Director and Director of the Distributor; Executive Vice
                                                                  President and Principal Executive Officer of the
                                                                  Institutional Funds (since July 2003) and the Retail Funds
                                                                  (since April 2003); Director of Morgan Stanley SICAV (since
                                                                  May 2004); previously, President and Director of the
                                                                  Institutional Funds (March 2001-July 2003) and Chief Global
                                                                  Operations Officer and Managing Director of Morgan Stanley
                                                                  Investment Management Inc.

Joseph J. McAlinden (62)       Vice President   Since July 1995   Managing Director and Chief Investment Officer of the
1221 Avenue of the Americas                                       Investment Adviser and Morgan Stanley Investment Management
New York, NY 10020                                                Inc.; Chief Investment Officer of the Van Kampen Funds; Vice
                                                                  President of the Institutional Funds (since July 2003) and
                                                                  the Retail Funds (since July 1995).

Barry Fink (50)                Vice President   Since             General Counsel (since May 2000) and Managing Director
1221 Avenue of the Americas                     February 1997     (since December 2000) of Morgan Stanley Investment
New York, NY 10020                                                Management; Managing Director (since December 2000),
                                                                  Secretary (since February 1997) and Director of the
                                                                  Investment Adviser and the Administrator; Vice President of
                                                                  the Retail Funds; Assistant Secretary of Morgan Stanley DW;
                                                                  Vice President of the Institutional Funds (since July 2003);
                                                                  Managing Director, Secretary and Director of the
                                                                  Distributor; previously Secretary (February 1997-July 2003)
                                                                  and General Counsel (February 1997-April 2004) of the Retail
                                                                  Funds; Vice President and Assistant General Counsel of the
                                                                  Investment Adviser and the Administrator (February 1997-
                                                                  December 2001).

Amy R. Doberman (43)           Vice President   Since July 2004   Managing Director and General Counsel, U.S. Investment
1221 Avenue of the Americas                                       Management; Managing Director of Morgan Stanley Investment
New York, NY 10020                                                Management Inc. and the Investment Adviser, Vice President
                                                                  of the Institutional and Retail Funds (since July 2004);
                                                                  Vice President of the Van Kampen Funds (since August 2004);
                                                                  previously, Managing Director and General Counsel -
                                                                  Americas, UBS Global Asset Management (July 2000-July 2004)
                                                                  and General Counsel, Aeltus Investment Management, Inc.
                                                                  (January 1997-July 2000).

Carsten Otto (41)              Chief            Since October     Executive Director and U.S. Director of Compliance for
1221 Avenue of the Americas    Compliance       2004              Morgan Stanley Investment Management (since October 2004);
New York, NY 10020             Officer                            Executive Director of the Investment Adviser and Morgan
                                                                  Stanley Investment Management Inc.; formerly Assistant
                                                                  Secretary and Assistant General Counsel of the Morgan
                                                                  Stanley Retail Funds.
</Table>

                                       26
<Page>

<Table>
<Caption>
                                                    TERM OF
                                 POSITION(S)      OFFICE AND
  NAME, AGE AND ADDRESS OF        HELD WITH        LENGTH OF
     EXECUTIVE OFFICER           REGISTRANT      TIME SERVED*             PRINCIPAL OCCUPATION(S) DURING PAST 5 YEARS**
- ----------------------------   ---------------  ---------------   ------------------------------------------------------------
                                                         
Stefanie V. Chang (38)         Vice President   Since July 2003   Executive Director of Morgan Stanley & Co. Incorporated,
1221 Avenue of the Americas                                       Morgan Stanley Investment Management Inc. and the Investment
New York, NY 10020                                                Adviser; Vice President of the Institutional Funds (since
                                                                  December 1997) and the Retail Funds (since July 2003);
                                                                  formerly practiced law with the New York law firm of Rogers
                                                                  & Wells (now Clifford Chance US LLP).

Francis J. Smith (39)          Treasurer and    Treasurer since   Executive Director of the Investment Adviser and the
c/o Morgan Stanley Trust       Chief Financial  July 2003 and     Administration (since December 2001); previously, Vice
Harborside Financial Center,   Officer          Chief Financial   President of the Retail Funds (September 2002-July 2003);
Plaza Two,                                      Officer since     Vice President of the Investment Adviser and the
Jersey City, NJ 07311                           September 2002    Administrator (August 2000-November 2001) and Senior Manager
                                                                  at PricewaterhouseCoopers LLP (January 1998-August 2000).

Thomas F. Caloia (59)          Vice President   Since July 2003   Executive Director (since December 2002) and Assistant
c/o Morgan Stanley Trust                                          Treasurer of the Investment Adviser, the Distributor and the
Harborside Financial Center,                                      Administrator; previously Treasurer of the Retail Funds
Plaza Two,                                                        (April 1989-July 2003); formerly First Vice President of the
Jersey City, NJ 07311                                             Investment Adviser, the Distributor and the Administrator.

Mary E. Mullin (38)            Secretary        Since July 2003   Executive Director of Morgan Stanley & Co. Incorporated,
1221 Avenue of the Americas                                       Morgan Stanley Investment Management Inc. and the Investment
New York, NY 10020                                                Adviser; Secretary of the Institutional Funds (since June
                                                                  1999) and the Retail Funds (since July 2003); formerly
                                                                  practiced law with the New York law firms of McDermott,
                                                                  Will & Emery and Skadden, Arps, Slate, Meagher & Flom LLP.
</Table>

- ----------
   * THIS IS THE EARLIEST DATE THE OFFICER BEGAN SERVING THE RETAIL FUNDS. EACH
     OFFICER SERVES AN INDEFINITE TERM, UNTIL HIS OR HER SUCCESSOR IS ELECTED.
  ** THE DATES REFERENCED BELOW INDICATING COMMENCEMENT OF SERVICE AS AN OFFICER
     FOR THE RETAIL AND INSTITUTIONAL FUNDS REFLECT THE EARLIEST DATE THE
     OFFICER BEGAN SERVING THE RETAIL OR INSTITUTIONAL FUNDS, AS APPLICABLE.


                       2005 FEDERAL TAX NOTICE (UNAUDITED)

          For the year ended June 30, 2005 all of the Fund's dividends
          from net investment income were exempt interest dividends,
          excludable from gross income for Federal income tax purposes.

                                       27
<Page>

TRUSTEES

Michael Bozic
Charles A. Fiumefreddo
Edwin J. Garn
Wayne E. Hedien
James F. Higgins
Dr. Manuel H. Johnson
Joseph J. Kearns
Michael E. Nugent
Fergus Reid

OFFICERS
Charles A. Fiumefreddo
CHAIRMAN OF THE BOARD

Mitchell M. Merin
PRESIDENT

Ronald E. Robison
EXECUTIVE VICE PRESIDENT and PRINCIPAL EXECUTIVE OFFICER

Joseph J. McAlinden
VICE PRESIDENT

Barry Fink
VICE PRESIDENT

Amy R. Doberman
VICE PRESIDENT

Carsten Otto
CHIEF COMPLIANCE OFFICER

Stefanie V. Chang
VICE PRESIDENT

Francis J. Smith
TREASURER and CHIEF FINANCIAL OFFICER

Thomas F. Caloia
VICE PRESIDENT

Mary E. Mullin
SECRETARY

TRANSFER AGENT
Morgan Stanley Trust
Harborside Financial Center, Plaza Two
Jersey City, New Jersey 07311

INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
Deloitte & Touche LLP
Two World Financial Center
New York, New York 10281

INVESTMENT ADVISER
Morgan Stanley Investment Advisors Inc.
1221 Avenue of the Americas
New York, New York 10020


This report is submitted for the general information of the shareholders of the
Fund. For more detailed information about the Fund, its fees and expenses and
other pertinent information, please read its Prospectus. The Fund's Statement of
Additional Information contains additional information about the Fund, including
its trustees. It is available, without charge, by calling (800) 869-NEWS.

This report is not authorized for distribution to prospective investors in the
Fund unless preceded or accompanied by an effective Prospectus. Read the
Prospectus carefully before investing.

Investments and services offered through Morgan Stanley DW Inc., member SIPC.
Morgan Stanley Distributors Inc., member NASD.

(C) 2005 Morgan Stanley

[MORGAN STANLEY LOGO]

RA05-00634P-Y06/05

[GRAPHIC]

                                                            MORGAN STANLEY FUNDS


                                                                   ACTIVE ASSETS
                                                                      CALIFORNIA
                                                                  TAX-FREE TRUST


                                                                   ANNUAL REPORT
                                                                    JUNE 30,2005


[MORGAN STANLEY LOGO]
<Page>

Item 2. Code of Ethics.

(a)    The Fund has adopted a code of ethics (the "Code of Ethics") that applies
to its principal executive officer, principal financial officer, principal
accounting officer or controller, or persons performing similar functions,
regardless of whether these individuals are employed by the Fund or a third
party.

(b)    No information need be disclosed pursuant to this paragraph.

(c)    The Fund has amended its Code of Ethics during the period covered by the
shareholder report presented in Item 1 hereto to delete from the end of the
following paragraph on page 2 of the Code the phrase "to the detriment of the
Fund.":

"Each Covered Officer must not use his personal influence or personal
relationship improperly to influence investment decisions or financial reporting
by the Fund whereby the Covered Officer would benefit personally (directly or
indirectly)."

(d)    Not applicable.

(e)    Not applicable.

(f)

       (1)    The Fund's Code of Ethics is attached hereto as Exhibit A.

       (2)    Not applicable.

       (3)    Not applicable.

Item 3. Audit Committee Financial Expert.

The Fund's Board of Trustees has determined that it has two "audit committee
financial experts" serving on its audit committee, each of whom are
"independent" Trustees: Dr. Manuel H. Johnson and Joseph J. Kearns. Under
applicable securities laws, a person who is determined to be an audit committee
financial expert will not be deemed an "expert" for any purpose, including
without limitation for the purposes of Section 11 of the Securities Act of 1933,
as a result of being designated or identified as an audit committee financial
expert. The designation or identification of a person as an audit committee
financial expert does not impose on such person any duties, obligations, or
liabilities that are greater than the duties, obligations, and liabilities
imposed on such person as a member of the audit committee and Board of Trustees
in the absence of such designation or identification.

<Page>

Item 4.  Principal Accountant Fees and Services.

(a)(b)(c)(d) and (g). Based on fees billed for the periods shown:

       2005

<Table>
<Caption>
                                                  REGISTRANT         COVERED ENTITIES(1)
                                                               
              AUDIT FEES                          $ 28,105           N/A

              NON-AUDIT FEES
                   AUDIT-RELATED FEES             $    540 (2)       $ 3,215,745 (2)
                   TAX FEES                       $  5,227 (3)       $    24,000 (4)
                   ALL OTHER FEES                 $      -           $         -
              TOTAL NON-AUDIT FEES                $  5,767           $ 3,239,745

              TOTAL                               $ 33,872           $ 3,239,745
</Table>

       2004

<Table>
<Caption>
                                                  REGISTRANT         COVERED ENTITIES(1)
                                                               
              AUDIT FEES                          $ 26,761           N/A

              NON-AUDIT FEES
                   AUDIT-RELATED FEES             $    452 (2)       $ 3,225,276 (2)
                   TAX FEES                       $  4,929 (3)       $   610,053 (4)
                   ALL OTHER FEES                 $      -           $         - (5)
              TOTAL NON-AUDIT FEES                $  5,381           $ 3,835,329

              TOTAL                               $ 32,142           $ 3,835,329
</Table>

              N/A- Not applicable, as not required by Item 4.

              (1) Covered Entities include the Adviser (excluding sub-advisors)
                  and any entity controlling, controlled by or under common
                  control with the Adviser that provides ongoing services to the
                  Registrant.
              (2) Audit-Related Fees represent assurance and related services
                  provided that are reasonably related to the performance of the
                  audit of the financial statements of the Covered Entities' and
                  funds advised by the Adviser or its affiliates, specifically
                  data verification and agreed-upon procedures related to asset
                  securitizations and agreed-upon procedures engagements.
              (3) Tax Fees represent tax compliance, tax planning and tax advice
                  services provided in connection with the preparation and
                  review of the Registrant's tax returns.
              (4) Tax Fees represent tax compliance, tax planning and tax advice
                  services provided in connection with the review of Covered
                  Entities' tax returns.
              (5) All other fees represent project management for future
                  business applications and improving business and operational
                  processes.

<Page>

(e)(1) The audit committee's pre-approval policies and procedures are as
follows:

                                                                      APPENDIX A

                                 AUDIT COMMITTEE
                          AUDIT AND NON-AUDIT SERVICES
                       PRE-APPROVAL POLICY AND PROCEDURES
                                     OF THE
                  MORGAN STANLEY RETAIL AND INSTITUTIONAL FUNDS

                    AS ADOPTED AND AMENDED JULY 23, 2004,(1)

  1.  STATEMENT OF PRINCIPLES

The Audit Committee of the Board is required to review and, in its sole
discretion, pre-approve all Covered Services to be provided by the Independent
Auditors to the Fund and Covered Entities in order to assure that services
performed by the Independent Auditors do not impair the auditor's independence
from the Fund.

The SEC has issued rules specifying the types of services that an independent
auditor may not provide to its audit client, as well as the audit committee's
administration of the engagement of the independent auditor. The SEC's rules
establish two different approaches to pre-approving services, which the SEC
considers to be equally valid. Proposed services either: may be pre-approved
without consideration of specific case-by-case services by the Audit Committee
("GENERAL PRE-APPROVAL"); or require the specific pre-approval of the Audit
Committee or its delegate ("SPECIFIC PRE-APPROVAL"). The Audit Committee
believes that the combination of these two approaches in this Policy will result
in an effective and efficient procedure to pre-approve services performed by the
Independent Auditors. As set forth in this Policy, unless a type of service has
received general pre-approval, it will require specific pre-approval by the
Audit Committee (or by any member of the Audit Committee to which pre-approval
authority has been delegated) if it is to be provided by the Independent
Auditors. Any proposed services exceeding pre-approved cost levels or budgeted
amounts will also require specific pre-approval by the Audit Committee.

The appendices to this Policy describe the Audit, Audit-related, Tax and All
Other services that have the general pre-approval of the Audit Committee. The
term of any general pre-approval is 12 months from the date of pre-approval,
unless the Audit Committee considers and provides a different period and states
otherwise. The Audit Committee will annually review and pre-approve the services
that may be provided by the Independent Auditors without obtaining specific
pre-approval from the Audit Committee. The Audit Committee will add to or
subtract from the list of general pre-approved services from time to time, based
on subsequent determinations.

- ----------
(1)    This Audit Committee Audit and Non-Audit Services Pre-Approval Policy and
       Procedures (the "POLICY"), adopted as of the date above, supersedes and
       replaces all prior versions that may have been adopted from time to time.

<Page>

The purpose of this Policy is to set forth the policy and procedures by which
the Audit Committee intends to fulfill its responsibilities. It does not
delegate the Audit Committee's responsibilities to pre-approve services
performed by the Independent Auditors to management.

The Fund's Independent Auditors have reviewed this Policy and believes that
implementation of the Policy will not adversely affect the Independent Auditors'
independence.

  2.  DELEGATION

As provided in the Act and the SEC's rules, the Audit Committee may delegate
either type of pre-approval authority to one or more of its members. The member
to whom such authority is delegated must report, for informational purposes
only, any pre-approval decisions to the Audit Committee at its next scheduled
meeting.

  3.  AUDIT SERVICES

The annual Audit services engagement terms and fees are subject to the specific
pre-approval of the Audit Committee. Audit services include the annual financial
statement audit and other procedures required to be performed by the Independent
Auditors to be able to form an opinion on the Fund's financial statements. These
other procedures include information systems and procedural reviews and testing
performed in order to understand and place reliance on the systems of internal
control, and consultations relating to the audit. The Audit Committee will
approve, if necessary, any changes in terms, conditions and fees resulting from
changes in audit scope, Fund structure or other items.

In addition to the annual Audit services engagement approved by the Audit
Committee, the Audit Committee may grant general pre-approval to other Audit
services, which are those services that only the Independent Auditors reasonably
can provide. Other Audit services may include statutory audits and services
associated with SEC registration statements (on Forms N-1A, N-2, N-3, N-4,
etc.), periodic reports and other documents filed with the SEC or other
documents issued in connection with securities offerings.

The Audit Committee has pre-approved the Audit services in Appendix B.1. All
other Audit services not listed in Appendix B.1 must be specifically
pre-approved by the Audit Committee (or by any member of the Audit Committee to
which pre-approval has been delegated).

  4.  AUDIT-RELATED SERVICES

Audit-related services are assurance and related services that are reasonably
related to the performance of the audit or review of the Fund's financial
statements and, to the extent they are Covered Services, the Covered Entities or
that are traditionally performed by the Independent Auditors. Because the Audit
Committee believes that the provision of Audit-related services does not impair
the independence of the auditor and is consistent with the SEC's rules on
auditor independence, the Audit Committee may grant general pre-approval to
Audit-related services. Audit-related services include, among others, accounting
consultations related to accounting, financial reporting or disclosure matters

<Page>

not classified as "Audit services"; assistance with understanding and
implementing new accounting and financial reporting guidance from rulemaking
authorities; agreed-upon or expanded audit procedures related to accounting
and/or billing records required to respond to or comply with financial,
accounting or regulatory reporting matters; and assistance with internal control
reporting requirements under Forms N-SAR and/or N-CSR.

The Audit Committee has pre-approved the Audit-related services in Appendix B.2.
All other Audit-related services not listed in Appendix B.2 must be specifically
pre-approved by the Audit Committee (or by any member of the Audit Committee to
which pre-approval has been delegated).

  5.  TAX SERVICES

The Audit Committee believes that the Independent Auditors can provide Tax
services to the Fund and, to the extent they are Covered Services, the Covered
Entities, such as tax compliance, tax planning and tax advice without impairing
the auditor's independence, and the SEC has stated that the Independent Auditors
may provide such services.

Pursuant to the preceding paragraph, the Audit Committee has pre-approved the
Tax Services in Appendix B.3. All Tax services in Appendix B.3 must be
specifically pre-approved by the Audit Committee (or by any member of the Audit
Committee to which pre-approval has been delegated).

  6.  ALL OTHER SERVICES

The Audit Committee believes, based on the SEC's rules prohibiting the
Independent Auditors from providing specific non-audit services, that other
types of non-audit services are permitted. Accordingly, the Audit Committee
believes it may grant general pre-approval to those permissible non-audit
services classified as All Other services that it believes are routine and
recurring services, would not impair the independence of the auditor and are
consistent with the SEC's rules on auditor independence.

The Audit Committee has pre-approved the All Other services in Appendix B.4.
Permissible All Other services not listed in Appendix B.4 must be specifically
pre-approved by the Audit Committee (or by any member of the Audit Committee to
which pre-approval has been delegated).

  7.  PRE-APPROVAL FEE LEVELS OR BUDGETED AMOUNTS

Pre-approval fee levels or budgeted amounts for all services to be provided by
the Independent Auditors will be established annually by the Audit Committee.
Any proposed services exceeding these levels or amounts will require specific
pre-approval by the Audit Committee. The Audit Committee is mindful of the
overall relationship of fees for audit and non-audit services in determining
whether to pre-approve any such services.

  8.  PROCEDURES

All requests or applications for services to be provided by the Independent
Auditors that do not require specific approval by the Audit Committee will be
submitted to the Fund's Chief Financial Officer and must include a detailed
description of the services to be

<Page>

rendered. The Fund's Chief Financial Officer will determine whether such
services are included within the list of services that have received the general
pre-approval of the Audit Committee. The Audit Committee will be informed on a
timely basis of any such services rendered by the Independent Auditors. Requests
or applications to provide services that require specific approval by the Audit
Committee will be submitted to the Audit Committee by both the Independent
Auditors and the Fund's Chief Financial Officer, and must include a joint
statement as to whether, in their view, the request or application is consistent
with the SEC's rules on auditor independence.

The Audit Committee has designated the Fund's Chief Financial Officer to monitor
the performance of all services provided by the Independent Auditors and to
determine whether such services are in compliance with this Policy. The Fund's
Chief Financial Officer will report to the Audit Committee on a periodic basis
on the results of its monitoring. Both the Fund's Chief Financial Officer and
management will immediately report to the chairman of the Audit Committee any
breach of this Policy that comes to the attention of the Fund's Chief Financial
Officer or any member of management.

  9.  ADDITIONAL REQUIREMENTS

The Audit Committee has determined to take additional measures on an annual
basis to meet its responsibility to oversee the work of the Independent Auditors
and to assure the auditor's independence from the Fund, such as reviewing a
formal written statement from the Independent Auditors delineating all
relationships between the Independent Auditors and the Fund, consistent with
Independence Standards Board No. 1, and discussing with the Independent Auditors
its methods and procedures for ensuring independence.

  10. COVERED ENTITIES

Covered Entities include the Fund's investment adviser(s) and any entity
controlling, controlled by or under common control with the Fund's investment
adviser(s) that provides ongoing services to the Fund(s). Beginning with
non-audit service contracts entered into on or after May 6, 2003, the Fund's
audit committee must pre-approve non-audit services provided not only to the
Fund but also to the Covered Entities if the engagements relate directly to the
operations and financial reporting of the Fund. This list of Covered Entities
would include:

       MORGAN STANLEY RETAIL FUNDS
       Morgan Stanley Investment Advisors Inc.
       Morgan Stanley & Co. Incorporated
       Morgan Stanley DW Inc.
       Morgan Stanley Investment Management Inc.
       Morgan Stanley Investment Management Limited
       Morgan Stanley Investment Management Private Limited
       Morgan Stanley Asset & Investment Trust Management Co., Limited
       Morgan Stanley Investment Management Company
       Van Kampen Asset Management
       Morgan Stanley Services Company, Inc.
       Morgan Stanley Distributors Inc.
       Morgan Stanley Trust FSB

<Page>

       MORGAN STANLEY INSTITUTIONAL FUNDS
       Morgan Stanley Investment Management Inc.
       Morgan Stanley Investment Advisors Inc.
       Morgan Stanley Investment Management Limited
       Morgan Stanley Investment Management Private Limited
       Morgan Stanley Asset & Investment Trust Management Co., Limited
       Morgan Stanley Investment Management Company
       Morgan Stanley & Co. Incorporated
       Morgan Stanley Distribution, Inc.
       Morgan Stanley AIP GP LP
       Morgan Stanley Alternative Investment Partners LP

(e)(2) Beginning with non-audit service contracts entered into on or after May
6, 2003, the audit committee also is required to pre-approve services to Covered
Entities to the extent that the services are determined to have a direct impact
on the operations or financial reporting of the Registrant. 100% of such
services were pre-approved by the audit committee pursuant to the Audit
Committee's pre-approval policies and procedures (attached hereto).

(f)    Not applicable.

(g)    See table above.

(h)    The audit committee of the Board of Trustees has considered whether the
provision of services other than audit services performed by the auditors to the
Registrant and Covered Entities is compatible with maintaining the auditors'
independence in performing audit services.

Item 5. Audit Committee of Listed Registrants.

(a) The Fund has a separately-designated standing audit committee established in
accordance with Section 3(a)(58)(A) of the Exchange Act whose members are:
Michael Bozic, Edwin J. Garn, Wayne E. Hedien, Manual H. Johnson, Joseph J.
Kearns, Michael Nugent and Fergus Reid.

(b) Not applicable.

Item 6. Schedule of Investments

Refer to Item 1.

<Page>

Item 7. Disclosure of Proxy Voting Policies and Procedures for Closed-End
Management Investment Companies.

Applicable only to reports filed by closed-end funds.

Item 8. Portfolio Managers of Closed-End Management Investment Companies

Applicable only to reports filed by closed-end funds.

Item 9. Closed-End Fund Repurchases

Applicable only to reports filed by closed-end funds.

Item 10. Submission of Matters to a Vote of Security Holders

Not applicable.

Item 11. Controls and Procedures

(a) The Fund's principal executive officer and principal financial officer have
concluded that the Fund's disclosure controls and procedures are sufficient to
ensure that information required to be disclosed by the Fund in this Form N-CSR
was recorded, processed, summarized and reported within the time periods
specified in the Securities and Exchange Commission's rules and forms, based
upon such officers' evaluation of these controls and procedures as of a date
within 90 days of the filing date of the report.

(b) There were no changes in the registrant's internal control over financial
reporting that occurred during the registrant's most recent fiscal half-year
(the registrant's second fiscal half-year in the case of an annual report) that
has materially affected, or is reasonably likely to materially affect, the
registrant's internal control over financial reporting.

Item 12. Exhibits

(a) The Code of Ethics for Principal Executive and Senior Financial Officers is
attached hereto.

(b) A separate certification for each principal executive officer and principal
financial officer of the registrant are attached hereto as part of EX-99.CERT.

<Page>

                                   SIGNATURES

     Pursuant to the requirements of the Securities Exchange Act of 1934 and the
Investment Company Act of 1940, the registrant has duly caused this report to be
signed on its behalf by the undersigned, thereunto duly authorized.

Active Assets California Tax-Free Trust

/s/ Ronald E. Robison
Ronald E. Robison
Principal Executive Officer
August 23, 2005

     Pursuant to the requirements of the Securities Exchange Act of 1934 and the
Investment Company Act of 1940, this report has been signed by the following
persons on behalf of the registrant and in the capacities and on the dates
indicated.

/s/ Ronald E. Robison
Ronald E. Robison
Principal Executive Officer
August 23, 2005

/s/ Francis Smith
Francis Smith
Principal Financial Officer
August 23, 2005