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                                                                  EXHIBIT 4.08



                      FOURTH AMENDMENT TO CREDIT AGREEMENT


     THIS FOURTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT, dated as
of March 31, 1997 (this "Amendment"), is among COMSHARE, INCORPORATED, a
Michigan corporation (the "Company"), the Banks set forth on the signature
pages hereof (collectively, the "Banks") and NBD BANK, formerly known as NBD
Bank, N.A., as agent for the Banks (in such capacity, the "Agent").


                                    RECITALS

     A. The Company, the Banks and the Agent are parties to an Amended and
Restated Credit Agreement, dated as of October 31, 1994, as amended by a First
Amendment to Credit Agreement dated May 19, 1995, a Second Amendment to Credit
Agreement dated July 31, 1995 and a Third Amendment to Credit Agreement dated
as of November 19, 1995 (the "Credit Agreement").

     B. The Company has requested that the Agent and the Banks amend the Credit
Agreement as set forth herein, and the Agent and the Banks have agreed to do
so.


                                     TERMS

     In consideration of the premises and of the mutual agreements herein
contained, the parties agree as follows:

ARTICLE I.  AMENDMENTS.  The Credit Agreement is amended as follows:

     1.1    The following definition shall be added to Section 1.1 in 
appropriate alphabetical order:

            "Funded Indebtedness" of any person shall mean, as of
            any date, the sum of all interest bearing indebtedness
            (including all obligations under Capital Leases) of
            such person.

     1.2    Clause (vi) of Section 5.2(c) is restated in its entirety to read 
as follows:

            (vi) As of March 31, 1997 and as of the last day of
            any fiscal quarter thereafter, the sum of $48,450,000
            plus (x) 50% of the Consolidated Net Income of the
            Company and its Subsidiaries, such Consolidated Net
            Income to be added as of the end of each fiscal
            quarter commencing with the fiscal quarter ending June
            30, 1997, provided that if such Consolidated Net
            Income is less than zero for any fiscal quarter, the 
            amount added for such fiscal quarter shall be zero, and 
            plus (y) 100% of the proceeds (net of any investment

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            banking fees, attorneys' fees, accountants' fees, underwriting      
            discounts and commissions and other customary fees and other costs
            and expenses actually incurred in connection with any offering of
            capital stock) of any capital stock or other equity securities      
            (including without limitation any securities exchangeable for or
            convertible into capital stock and any warrants, rights or other
            options to purchase or otherwise acquire capital stock, excluding,
            however, any of the foregoing, including any capital stock or other
            equity securities, which are sold to any director, officer or other
            employee of the Company pursuant to any stock option plan or other
            benefit or compensation plan for any director, officer or employee
            of the Company) of the Company offered or otherwise sold at any
            time after March 31, 1997.


     1.3    A new Section 5.2(o) shall be added at the end of Section 5.2 to 
read as follows:

            (o) Cash.  Permit or suffer consolidated cash of the
            Company and its Subsidiaries minus $2,500,000 minus
            consolidated Funded Indebtedness of the Company and
            its Subsidiaries at any time to be less than $0.

ARTICLE II.  REPRESENTATIONS.  The Company represents and warrants to the Agent
and the Banks that:

     2.1    The execution, delivery and performance of this Amendment is within
its powers, has been duly authorized and is not in contravention with any law,
of the terms of its Articles of Incorporation or By-laws, or any undertaking to
which it is a party or by which it is bound.

     2.2    This Amendment is the legal, valid and binding obligation of the
Company enforceable against it in accordance with the terms hereof.

     2.3    After giving effect to the amendments herein contained, the 
warranties contained in Article IV of the Credit Agreement are true on and as 
of the date hereof with the same force and effect as if made on and as of the 
date hereof.

     2.4    After giving effect to the amendments herein contained, no Event of
Default or Default exists or has occurred and is continuing on the date hereof.


ARTICLE III.  MISCELLANEOUS.


     3.1    References in the Credit Agreement or in any note, certificate,
instrument or other document to the Credit Agreement shall be deemed to be
references to the Credit Agreement as




FOURTH AMENDMENT TO CREDIT AGREEMENT                                     Page 2

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amended hereby and as further amended from time to time.

     3.2    The Company agrees to pay and to hold the Agent and the Banks 
harmless for the payment of all costs and expenses arising in connection
with this Amendment, including the reasonable fees of counsel to the Agent in
connection with preparing this Amendment.

     3.3    Except as expressly amended hereby, the Company agrees that the 
Credit Agreement, the Notes, the Security Documents and all other documents and
agreements (which have not been previously terminated) executed by the Company
in connection with the Credit Agreement in favor of the Agent or the Banks are
ratified and confirmed and shall remain in full force and effect and that it
has no set off, counterclaim or defense with respect to any of the foregoing.
Terms used but not defined herein shall have the respective meanings ascribed
thereto in the Credit Agreement.

     3.4    This Amendment may be signed upon any number of counterparts with 
the same effect as if the signatures thereto and hereto were upon the same
instrument.

     IN WITNESS WHEREOF, the parties signing this Amendment have caused this
Amendment to be executed and delivered as May 12, 1997 to be effective as of
March 31, 1997.

                                    COMSHARE, INCORPORATED


                                    By: /s/ Kathryn Jehle
                                        --------------------------------
                                     Its:    SVP & CFO
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                                    NBD BANK, formerly known as NBD Bank, N.A.,
                                    Individually as a Bank and as Agent


                                    By: /s/  Martha Radek-Smith
                                        --------------------------------
                                     Its:   Vice President
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FOURTH AMENDMENT TO CREDIT AGREEMENT                                     Page 3