SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                  SCHEDULE TO/A
                                 (Rule 14d-100)
            TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1)
                     OF THE SECURITIES EXCHANGE ACT OF 1934
                                (AMENDMENT NO. 4)

                             COMSHARE, INCORPORATED
                       (Name of Subject Company (Issuer))

                           CONDUCTOR ACQUISITION CORP.
                                    (Offeror)
                     an indirect wholly-owned subsidiary of
                        GEAC COMPUTER CORPORATION LIMITED
                               (Parent of Offeror)
                            (Names of Filing Persons)

                     COMMON STOCK, PAR VALUE $1.00 PER SHARE
                         (Title of Class of Securities)

                                    205912108
                      (CUSIP Number of Class of Securities)

                                CHARLES S. JONES
                      PRESIDENT AND CHIEF EXECUTIVE OFFICER
                        GEAC COMPUTER CORPORATION LIMITED
                         11 ALLSTATE PARKWAY, SUITE 300
                            MARKHAM, ONTARIO L3R 9T8
                                     CANADA
                                 (905) 475-0525
           (Name, address, and telephone numbers of person authorized
       to receive notices and communications on behalf of filing persons)

                                 with copies to:
                          ROBERT W. SWEET, JR., ESQUIRE
                                 FOLEY HOAG LLP
                              155 SEAPORT BOULEVARD
                           BOSTON, MASSACHUSETTS 02210

                            CALCULATION OF FILING FEE



Transaction valuation*                                    Amount of filing fee**
- ----------------------                                    ----------------------
                                                       
     $52,008,427                                                $4,208 ***


*Estimated for purposes of calculating the amount of the filing fee only. This
amount assumes the purchase at $4.60 per share in cash, pursuant to the Offer to
Purchase, of all 10,827,583 issued and outstanding shares of common stock, par
value $1.00 per share, of Comshare, Incorporated as of June 30, 2003 plus the
aggregate amount in cash to be paid to holders of outstanding options to
purchase shares of Comshare common stock determined by multiplying the excess,
if any, of $4.60 over the applicable exercise price of each such option by the
number of shares of Comshare common stock underlying such option.

**The amount of the filing fee, calculated in accordance with Rule 0-11 of the
Securities Exchange Act of 1934, as amended, equals $80.90 per $1,000,000 of the
transaction value.

***Previously paid in connection with the Offerors' Schedule TO filed with the
Securities and Exchange Commission on July 1, 2003.

[ ]   Check the box if any part of the fee is offset as provided by Rule
      0-11(a)(2) and identify the filing with which the offsetting fee was
      previously paid. Identify the previous filing by registration statement
      number, or the Form or Schedule and the date of its filing.

                     Amount Previously Paid:

                     Form or Registration No.:

                     Filing Party:

                     Date Filed:

[ ]   Check the box if the filing relates solely to preliminary communications
      made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the
statement relates:

[X]    third-party tender offer subject to Rule 14d-1.

[ ]    issuer tender offer subject to Rule 13e-4.

[ ]    going-private transaction subject to Rule 13e-3.

[ ]    amendment to Schedule 13D under Rule 13d-2

Check the following box if the filing is a final amendment reporting the results
of the tender offer: [ ]


- --------------------------------------------------------------------------------

                                   SCHEDULE TO

      This Amendment No. 4 amends and supplements the Tender Offer Statement on
Schedule TO filed with the Securities and Exchange Commission on July 1, 2003,
as amended by Amendment No. 1 filed on July 17, 2003, Amendment No. 2 filed on
July 18, 2003 and Amendment No. 3 filed on July 31, 2003 (as amended, the
"Schedule TO"), by Geac Computer Corporation Limited, a corporation governed by
the Canada Business Corporations Act ("Geac") and Conductor Acquisition Corp., a
Michigan corporation ("Purchaser") and an indirect wholly owned subsidiary of
Geac. The Schedule TO relates to the offer by Purchaser to purchase all of the
outstanding shares of common stock, par value $1.00 per share (the "Shares"), of
Comshare, Incorporated, a Michigan corporation (the "Company"), at a purchase
price of $4.60 per Share, net to the seller in cash, without interest thereon,
upon the terms and subject to the conditions set forth in the Offer to Purchase,
dated July 1, 2003, as amended, filed as Exhibit (a)(1)(A) to the Schedule TO
(the "Offer to Purchase"), and in the related Letter of Transmittal filed as
Exhibit (a)(1)(B) to the Schedule TO. The item numbers and responses thereto
below are in accordance with the requirements of Schedule TO. Unless otherwise
defined herein, all capitalized terms used herein shall have the respective
meanings given to such terms in the Offer to Purchase.

ITEMS 11

      Item 11 of the Schedule TO is hereby amended and supplemented to add the
following:

      "The Offer expired at 12:00 midnight, Eastern time, on Thursday, July 31,
2003. Upon expiration of the Offer, Purchaser accepted all validly tendered
Shares for payment in accordance with the terms of the Offer. EquiServe Trust
Company, N.A., the depositary for the Offer (the "Depositary"), has advised Geac
and Purchaser that, as of the expiration of the Offer, an aggregate of 8,905,339
Shares were validly tendered to the Purchaser in the Offer, and an additional
169,479 Shares were delivered through notices of guaranteed delivery. The
8,905,339 Shares validly tendered represent approximately 82.2% of the Shares
outstanding.

      "On August 1, 2003, Geac issued a press release, a copy of which is
attached hereto as Exhibit (a)(1)(J) and incorporated by reference herein,
announcing that Purchaser accepted all Shares validly tendered in the Offer and
that Purchaser commenced a subsequent offering period for all remaining
untendered Shares expiring at 5:00 p.m., Eastern time, on Monday, August 11,
2003, unless further extended. Purchaser will immediately accept all Shares
properly tendered during the subsequent offering period and will pay the
tendering stockholders promptly after acceptance. The same $4.60 per Share price
offered in the prior offering period will be paid during the subsequent offering
period. Shares tendered during the subsequent offering period may not be
withdrawn. Geac and Purchaser reserve the right to extend the subsequent
offering period in accordance with applicable law.

      "Also on August 1, 2003, Geac issued a second press release, a copy a copy
of which is attached hereto as Exhibit (a)(1)(K) and incorporated by reference
herein, announcing, among other things, that James S. Travers has been appointed
President and Chief Executive Officer of the Company and that Anna C. Forgione,
Steven Horniak, Ruth Klein, Derek J. Murphy, Lou J. Pagotto and James M. Riley
have been appointed to the Board of Directors of the Company.


                                      -3-

      "Pursuant to the terms of the Merger Agreement, Geac will cause the merger
of Purchaser with and into the Company as soon as practicable. As a result of
the Merger, each issued and outstanding Share that was not tendered in the Offer
(other than Shares that are owned by Geac or the Company or any of their
respective wholly owned subsidiaries, all of which will be cancelled without any
consideration being exchanged therefor) will be, by virtue of the Merger and
without any action on the part of the holder thereof, converted into the right
to receive the same price paid in the Offer, that is $4.60 in cash, without
interest thereon and less any required withholding taxes, upon surrender of the
certificate representing such Share, and the Company will become an indirect
wholly owned subsidiary of Geac."

ITEM 12. EXHIBITS.

      Item 12 of the Schedule TO is hereby amended and supplemented to add the
following:

      "(a)(1)(J) Press Release dated August 1, 2003."

      "(a)(1)(K) Press Release dated August 1, 2003."


                                      -4-

                                    SIGNATURE

After due inquiry and to the best of my knowledge and belief, I certify that the
information set forth in this statement is true, complete and correct.

                                       GEAC COMPUTER CORPORATION LIMITED

                                       /s/ Craig C. Thorburn
                                       -----------------------------------------
                                       By:  Craig C. Thorburn
                                       Its:   Senior Vice President, Mergers &
                                       Acquisitions, and Corporate Secretary


                                       CONDUCTOR ACQUISITION CORP.

                                       /s/ Craig C. Thorburn
                                       -----------------------------------------
                                       By:  Craig C. Thorburn
                                       Its:   Vice President

Date: August 1, 2003


                                      -5-

                                INDEX TO EXHIBITS



EXHIBIT NUMBER                      DESCRIPTION
- --------------                      -----------
               
(a) (1) (A)       Offer to Purchase, dated July 1, 2003.*

(a) (1) (B)       Letter of Transmittal.*

(a) (1) (C)       Notice of Guaranteed Delivery.*

(a) (1) (D)       Letter to Brokers, Dealers, Banks, Trust Companies and other
                  Nominees.*

(a) (1) (E)       Letter to Clients for use by Brokers, Dealers, Banks, Trust
                  Companies and other Nominees.*

(a) (1) (F)       Press Release dated July 1, 2003.*

(a) (1) (G)       Summary Advertisement, published in the New York Times on July
                  3, 2003.*

(a) (1) (H)       Press Release dated July 16, 2003.**

(a) (1) (I)       Press Release dated July 31, 2003.***

(a) (1) (J)       Press Release dated August 1, 2003.

(a) (1) (K)       Press Release dated August 1, 2003.

(b)               Not Applicable.

(c)               Not Applicable.

(d) (1)           Confidentiality Agreement dated April 24, 2003 between Geac
                  and the Company.*

(d) (2)           Confidentiality Agreement effective May 1, 2003 between Geac
                  and the Company.*

(d) (3)           Agreement and Plan of Merger, dated as of June 22, 2003, by
                  and among Geac, Purchaser and the Company.*

(d) (4)           Voting and Tender Agreement, dated as of June 22, 2003, by and
                  among Geac, Purchaser and Dennis G. Ganster.*

(d) (5)           Voting and Tender Agreement, dated as of June 22, 2003, by and
                  among Geac, Purchaser and each of Codec Systems Limited and
                  Anthony Stafford.*

(d) (6)           Employment agreement dated June 19, 2003 by and among the
                  Company, Geac Computers, Inc., Geac and Brian Hartlen.*

(d) (7)           Employment agreement dated June 19, 2003 by and among the
                  Company, Geac Computers, Inc., Geac and David King.*

(g)               Not Applicable.

(h)               Not Applicable.



                                      -6-

*     Previously filed on July 1, 2003 with the Securities and Exchange
      Commission on Schedule TO by Purchaser and Geac.

**    Previously filed on July 17, 2003 with the Securities and Exchange
      Commission on Schedule TO by Purchaser and Geac.

***   Previously filed on July 31, 2003 with the Securities and Exchange
      Commission on Schedule TO by Purchaser and Geac.


                                      -7-