EXHIBIT 2.3

                           VOTING AND TENDER AGREEMENT

         This Voting and Tender Agreement (this "Agreement"), dated as of
June 22, 2003, is entered into by and among Geac Computer Corporation
Limited, a corporation governed by the Canada Business Corporations Act
("Parent"), Conductor Acquisition Corp., a Michigan corporation and an indirect
wholly-owned subsidiary of Parent ("Merger Subsidiary"), and Dennis G. Ganster
(the "Stockholder").

                              W I T N E S S E T H:

         WHEREAS, Parent, Merger Subsidiary and Comshare, Incorporated, a
Michigan corporation ("Company"), are entering into an Agreement and Plan of
Merger, dated as of the date hereof (the "Merger Agreement") pursuant to which
Merger Subsidiary has agreed to make a tender offer (the "Offer") for all
outstanding shares of common stock, par value $1.00 per share, of the Company
(the "Common Stock"), together with any associated Rights, at a price per share
of $4.60, net to the seller in cash, without interest (such price, or such
higher price per share of Common Stock as may be paid in the Offer, being
referred to herein as the "Offer Price"), to be followed by a merger (the
"Merger") of Merger Subsidiary with and into the Company (all capitalized terms
not otherwise defined herein shall have the meanings given to them in the Merger
Agreement);

         WHEREAS, the Stockholder holds 130,870 shares of the Common Stock (the
"Shares;" provided that, for purposes of this Agreement, the term "Shares" shall
include any associated Rights);

         WHEREAS, as a condition to the willingness of Parent and Merger
Subsidiary to enter into the Merger Agreement, each of Parent and Merger
Subsidiary has required that the Stockholders agree, and in order to induce
Parent and Merger Subsidiary to enter into the Merger Agreement, the Stockholder
has agreed, to enter into this Agreement simultaneously with the execution and
delivery by the parties thereto of the Merger Agreement.

         NOW, THEREFORE, in consideration of the mutual covenants and agreements
contained herein and other good and valuable consideration, the adequacy of
which is hereby acknowledged, and intending to be legally bound hereby, the
parties hereto agree as follows:

1. Tender by Stockholder.

         1.1 Tender of Shares. Subject to Section 6 below, the Stockholder
agrees to tender and sell to Merger Subsidiary, not later than one (1) business
day prior to the initial expiration date of the Offer, without regard to any
extension thereof (the "Initial Expiration Date"), all the Shares (and any
shares of Common Stock, and any associated Rights, acquired by the Stockholder
subsequent to the date hereof but prior to the consummation of the Tender
Offer), pursuant to and in accordance with the Offer. The Stockholder agrees
that he shall deliver or cause to be delivered to the depositary for the Offer,
not later than one (1) business day before the Initial Expiration Date of the
Offer, either a letter of transmittal together with the certificates for the
Shares, if available, or a "Notice of Guaranteed Delivery," if the Shares are
not available.







After such tender the Stockholders shall not withdraw any such Shares, until
this Agreement is terminated in accordance with its terms.

         1.2 Adjustments Upon Changes in Capitalization. In the event of any
change in the number of issued and outstanding shares of Common Stock by reason
of any stock dividend, subdivision, merger, recapitalization, combination,
conversion or exchange of shares, or any other change in the corporate or
capital structure of the Company (including, without limitation, the declaration
or payment of an extraordinary dividend of cash or securities), the term
"Shares" shall be deemed to refer to and include the Shares as well as all such
stock dividends and distributions and any shares into which or for which any or
all of the Shares may be changed or exchanged.

2. Representations and Warranties of the Stockholder. The Stockholder represents
and warrants to Parent and Merger Subsidiary that:

         2.1 Power and Authority. The Stockholder has all necessary power and
authority to enter into and perform all of his obligations under this Agreement
and to sell, assign, transfer and deliver to Parent and/or Merger Subsidiary,
pursuant to the terms and subject to the conditions of this Agreement and the
Merger Agreement, the Shares that he legally and/or beneficially owns. This
Agreement and the Stockholder's consummation of the transactions contemplated
hereby have been duly and validly authorized, executed and delivered by the
Stockholder.

         2.2 No Other Rights. Except for this Agreement, there are no
outstanding options, warrants or rights to purchase or acquire any of the
Shares.

         2.3 Only Shares. The Stockholder is the beneficial owner of all of the
Shares. On the date hereof, the Shares constitute all of the shares of Common
Stock of the Company owned of record or beneficially owned by the Stockholder
other than Stock Options (as defined in the Merger Agreement), shares to be
acquired through the Company's Employee Stock Purchase Plan and shares owned by
the Stockholder's spouse. The Stockholder has sole voting power and sole power
to issue instructions with respect to the matters set forth in Section 1 hereof,
sole power of disposition and sole power to agree to all of the matters set
forth in this Agreement, in each case with respect to all of the Shares, with no
limitations, qualifications or restrictions on such rights (subject to
applicable securities laws). There is no beneficiary or holder of a voting trust
certificate or other interest of any trust of which the Stockholder is settlor
or trustee or any other person whose consent is required for the execution,
delivery and performance of this Agreement or the consummation by the
Stockholder of the transactions contemplated hereby.

         2.4 Title. The Stockholder is the beneficial owner of all of the Shares
held by such Stockholder and has, and upon the closing of the Offer, Merger
Subsidiary shall receive, good and marketable title to such Shares, free and
clear of all liens, claims, encumbrances and security interests of any nature
whatsoever.

         2.5 Validity. This Agreement has been duly and validly executed and
delivered by the Stockholder and constitutes the legal, valid and binding
agreement of the Stockholder, enforceable against the Stockholder in accordance
with its terms, except as enforcement may be limited by applicable bankruptcy,
insolvency, fraudulent conveyance, reorganization,


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moratorium or other similar laws relating to creditors' rights generally and
except that the availability of legal and equitable remedies, including specific
performance, is subject to general principles of equity, including principles of
commercial reasonableness, good faith and fair dealing and the discretion of the
court before which any proceeding therefor may be brought.

         2.6 Non-Contravention. The execution, delivery and performance of this
Agreement does not, and the consummation of the transactions contemplated hereby
and compliance with the provisions hereof will not, contravene, conflict with,
or result in any violation of, breach of or default by (with or without notice
or lapse of time, or both) the Stockholder under, or give rise to a right of
termination, cancellation or acceleration of any obligation under, or result in
the creation of any Lien, security interest, charge or encumbrance upon any of
the properties or assets of the Stockholder under, any provision of: (i) any
loan or credit agreement, note, bond, mortgage, indenture, lease or other
agreement, instrument, permit, concession, franchise or license applicable to
such Stockholder or (ii) any judgment, order, decree, statute, law, ordinance,
injunction, rule or regulation applicable to such Stockholder or any of his
properties or assets, other than, in the case of clauses (i) and (ii), any such
conflicts, violations, defaults, rights, liens, security interests, charges or
encumbrances that, individually or in the aggregate, would not materially impair
the ability of such Stockholder to perform his obligations hereunder or prevent,
limit or restrict the consummation of any of the transactions contemplated
hereby.

3. Representations and Warranties of Parent and Merger Subsidiary. Parent and
Merger Subsidiary, jointly and severally, represent and warrant to the
Stockholder that:

         3.1 Power and Authority. Each of Parent and Merger Subsidiary has the
requisite corporate power and authority to execute and deliver this Agreement,
to perform its obligations hereunder and to consummate the transactions
contemplated hereby. This Agreement and the consummation by Parent and Merger
Subsidiary of the transactions contemplated hereby have been duly and validly
authorized by each of Parent and Merger Subsidiary, and no other corporate
action or proceedings on the part of Parent and Merger Subsidiary are necessary
to authorize this Agreement or to consummate the transactions contemplated
hereby.

         3.2 Validity. This Agreement has been duly and validly executed and
delivered by each of Parent and Merger Subsidiary and constitutes the legal,
valid and binding agreement of each of Parent and Merger Subsidiary, enforceable
against each of them in accordance with its terms, except as enforcement may be
limited by applicable bankruptcy, insolvency, fraudulent conveyance,
reorganization, moratorium or other similar laws relating to creditors' rights
generally and except that the availability of legal and equitable remedies,
including specific performance, is subject to general principles of equity,
including principles of commercial reasonableness, good faith and fair dealing
and the discretion of the court before which any proceeding therefor may be
brought.

         3.3 Non-Contravention. The execution, delivery and performance of this
Agreement does not, and the consummation of the transactions contemplated hereby
and compliance with the provisions hereof will not, contravene, conflict with,
or result in any violation of, breach of or default by (with or without notice
or lapse of time, or both) either of Parent or Merger Subsidiary under, or give
rise to a right of termination, cancellation or acceleration of any obligation
under, or result in the creation of any Lien, security interest, charge or
encumbrance upon any of the


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properties or assets of either Parent or Merger Subsidiary under, any provision
of: (i) the charter or organizational documents of Parent or Merger Subsidiary,
(ii) any loan or credit agreement, note, bond, mortgage, indenture, lease or
other agreement, instrument, permit, concession, franchise or license applicable
to Parent or Merger Subsidiary or (iii) any judgment, order, decree, statute,
Law, ordinance, injunction, rule or regulation applicable to Parent or Merger
Subsidiary or any of their properties or assets, other than, in the case of
clauses (ii) and (iii), any such conflicts, violations, defaults, rights, liens,
security interests, charges or encumbrances that, individually or in the
aggregate, would not materially impair the ability of Parent or Merger
Subsidiary to perform its obligations hereunder or prevent, limit or restrict
the consummation of any of the transactions contemplated hereby.

4. Covenants of the Stockholder.

         4.1 No Disposition or Encumbrance of Shares; No Proxies. The
Stockholder represents, covenants and agrees that, except for the proxy granted
in Section 5 and as contemplated by this Agreement: (a) he shall not, directly
or indirectly, during the period commencing on the date hereof and continuing
until this provision terminates pursuant to Section 7 hereof: offer for sale or
agree to sell, transfer, tender, assign, pledge, hypothecate or otherwise
dispose of or enter into any contract, option or other arrangement or
understanding with respect to, or consent to, the offer for sale, sale,
transfer, tender, pledge, hypothecation, encumbrance, assignment or other
disposition of, or create any security interest, Lien, claim, pledge, option,
right of first refusal, agreement, limitation on voting rights, charge or other
encumbrance of any nature whatsoever with respect to any or all of the Shares or
any interest thereon now legally and/or beneficially owned by the Stockholder,
or that may hereafter be acquired by, the Stockholder; (b) he shall not grant
any proxy, irrevocable proxy or power of attorney or deposit any Shares into a
voting trust or enter into a voting agreement with respect to the voting of
Shares (each a "Voting Proxy") to any person except to vote in favor of any of
the Transactions contemplated by this Agreement or the Merger Agreement; (c) he
has granted no Voting Proxy which is currently (or which will hereafter become)
effective with respect to the Shares, and if any Voting Proxy has been granted
to any person, such Voting Proxy is hereby revoked; (d) no Voting Proxy shall be
given or written consent executed by the Stockholder after the date hereof with
respect to the Shares (and if given or executed, shall not be effective) so long
as this Agreement remains in effect; and (e) he shall not, and shall not offer
to agree to, acquire any additional shares of Common Stock, or options, warrants
or other rights to acquire shares of Common Stock (except upon exercise of Stock
Options presently held by the Stockholder or pursuant to the Company's Employee
Stock Purchase Plan), without the prior written consent of Parent or Merger
Subsidiary.

5. Voting Agreement. The Stockholder agrees that, during the time this Agreement
is in effect, at any meeting of the stockholders of the Company, however called,
and in any action by written consent of the stockholders of the Company, he
shall vote all of the Shares legally and/or beneficially owned by him (i) in
favor of the Merger, the Merger Agreement and any of the transactions
contemplated by the Merger Agreement (as amended from time to time, except for
an amendment, modification or waiver that results in termination of the
Agreement pursuant to Section 7 hereof); (ii) against any action or agreement
that would result in a breach in any material respect of any covenant,
representation or warranty or any other obligation of the Company under the
Merger Agreement; and (iii) against any action or agreement that would


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materially impede, interfere with or attempt to discourage the Offer or the
Merger. The Stockholder hereby irrevocably grants to and appoints Parent as the
Stockholder's proxy and attorney-in-fact (with full power of substitution), for
and in the name, place and stead of the Stockholder, to vote, act by written
consent or grant a consent, proxy or approval in respect of all Shares held by
the Stockholder with respect to such vote or action by written consent, solely
for the purposes of voting in favor of the Merger, the Merger Agreement (as
amended from time to time, except for an amendment, modification or waiver that
results in termination of the Agreement pursuant to Section 7 hereof); and any
of the transactions contemplated by the Merger Agreement. The Stockholder hereby
affirms that such proxy shall be irrevocable and shall be deemed coupled with an
interest, in accordance with Section 422 of the Michigan Law (as defined in the
Merger Agreement). This proxy shall lapse and be of no further force and effect
from and after the date of this Agreement is terminated pursuant to Section 7
hereof.

6. Sophistication. The Stockholder acknowledges being a sophisticated investor
who, together with his financial advisors and independent legal counsel, has
undertaken such investigation as they have deemed necessary, including inquiries
of the Company and review of the Merger Agreement and this Agreement, to enable
the Stockholder to make an informed and intelligent decision with respect to the
Merger Agreement and this Agreement and the transactions contemplated hereby.

7. Effectiveness; Termination; No Survival. This Agreement shall become
effective upon its execution by the Stockholder, Parent and Merger Subsidiary
and upon the execution of the Merger Agreement. This Agreement may be terminated
as to the Stockholder at any time by mutual written consent of the Stockholder,
Parent and Merger Subsidiary. This Agreement, and all the obligations of the
Stockholder hereunder, including, without limitation, his obligations under
Sections 1, 4 and 5 above, shall terminate, without any action by the parties
hereto, upon the earliest to occur of (a) in the event of an amendment or
modification to or waiver under the Merger Agreement (including, without
limitation, the terms and conditions of the Offer) that is or would be adverse
to the Stockholder, including without limitation any reduction of the Offer
Price or the number of shares sought in the Offer, change of the form of
consideration to be paid, or waiver of the Minimum Condition, upon such
amendment, modification, waiver or reduction, (b) in the event the Merger
Agreement is terminated by any party in accordance with its terms, upon such
termination, (c) in the event the Merger is consummated, upon the Effective Time
(as defined in the Merger Agreement) or (d) December 31, 2003. The
representations and warranties of the parties set forth in Sections 2 and 3
hereof shall not survive the termination of this Agreement. Notwithstanding
anything to the contrary herein, no termination of this Agreement shall relieve
the parties of liability for breach hereof prior to such termination.

8. Further Assurances. Subject to the terms of this Agreement, from time to
time, the Stockholder shall execute and deliver such additional documents and
use his commercially reasonable best efforts to take, or cause to be taken, all
such further actions, and to do or cause to be done, all things reasonably
necessary, proper or advisable in the most expeditious manner possible, under
applicable laws and regulations to consummate and make effective the
transactions contemplated by this Agreement.

9. Miscellaneous.




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         9.1 Notices. Any notice request, instruction or other document to be
given hereunder by any party to the other parties shall be in writing and
delivered personally or sent by overnight courier, registered or certified mail,
postage prepaid, or by facsimile transmission, as follows:

                  if to Parent or Merger Subsidiary, to:

                           Geac Computer Company Limited
                           11 Allstate Parkway, Suite 300
                           Markham, Ontario L3R 9T8
                           Facsimile:  (905) 940-3722
                           Attention:  Chief Executive Officer

                           with a copy (which shall not constitute notice) to
                           each of:

                           Blake, Cassels & Graydon LLP
                           Commerce Court West
                           199 Bay Street, Suite 2800
                           Toronto, Ontario M5L 1A9
                           Facsimile:  (916) 863-2653
                           Attention:  Craig Thorburn, Esq.

                           and

                           Foley Hoag LLP
                           World Trade Center West
                           155 Seaport Boulevard
                           Boston, Massachusetts 02210
                           Facsimile:  (617) 832-1000
                           Attention:  Robert W. Sweet, Jr., Esq.

                  if to the Stockholder, at its address set forth on Exhibit A
                  hereto:

                           with a copy (which shall not constitute notice) to
                           each of:

                           Comshare Incorporated
                           555 Briarwood Circle
                           Ann Arbor, MI 48108
                           Facsimile:  (734) 205-0143
                           Attention:  Chief Executive Officer


                           and

                           Dykema Gossett PLLC
                           400 Renaissance Center
                           Detroit, MI 48243-1668
                           Facsimile:  (313) 568-6915
                           Attention:  Thomas S. Vaughn, Esq.




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         9.2 Waivers and Amendment. Any provision of this Agreement may be
waived at any time by the party which is entitled to the benefits thereof. This
Agreement may not be amended, changed, supplemented or otherwise modified except
upon the execution and delivery of a written agreement executed by all of the
parties hereto.

         9.3 Entire Agreement. This Agreement and the Merger Agreement contain
the entire agreement, and supersede all other prior and contemporaneous
agreements and understandings, both written and oral, among the parties hereto
with respect to the subject matter hereof. This Agreement is not intended to
confer upon any other person any rights or remedies hereunder.

         9.4 Successors and Assigns. This Agreement shall not be assigned by any
party hereto, except that Parent or Merger Subsidiary may assign its rights
under this Agreement to another direct or indirect wholly-owned subsidiary of
Parent, but such assignment shall not relieve Parent or Merger Subsidiary of its
respective obligations hereunder. This Agreement shall be binding upon, inure
solely to the benefit of and be enforceable by and against the parties hereto
and their successors (including heirs, administrators and executors of
individuals) and permitted assigns. Nothing in this Agreement, express or
implied, is intended to or shall confer upon any other person, any rights,
benefits or remedies of any nature whatsoever under or by reason of this
Agreement.

         9.5 Remedies. Each of the parties hereto acknowledges and agrees that
each other party would be irreparably damaged in the event any of the provisions
of this Agreement were not performed by the other in accordance with their
specific terms or were otherwise breached. It is accordingly agreed that each
party shall be entitled to an injunction or injunctions to redress any breaches
of this Agreement and to specifically enforce the terms and provisions hereof in
any action instituted in any court of the United States or any state thereof
having jurisdiction, in addition to any other remedy to which such party may be
entitled at law or in equity.

         9.6 Expenses. Each of the parties shall pay its own expenses in
connection with the negotiation, execution and performance of this Agreement.

         9.7 Counterparts. This Agreement and any amendments hereto may be
executed in two or more counterparts, each of which shall be considered to be an
original, both of which together shall constitute the same instrument.

         9.8 Governing Law. This Agreement shall be governed by and construed in
accordance with the laws of the State of Michigan, without regard to the
principles of conflicts of laws thereof.

         9.9 Severability. If any term, provision, covenant or restriction of
this Agreement is held by a court of competent jurisdiction to be invalid, void
or unenforceable, the remainder of the terms, provisions, covenants and
restrictions of this Agreement shall remain in full force and effect and shall
in no way be affected, impaired or invalidated.

         9.10 Effect of Headings. The section headings herein are for
convenience only and shall not affect the meaning or interpretation of this
Agreement.




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         9.11 Stockholder Capacity. Notwithstanding anything herein to the
contrary, the Stockholder makes no agreement or understanding herein in his
capacity as a director or officer of the Company or any subsidiary of the
Company, and the agreements set forth herein shall in no way restrict the
Stockholder in the exercise of his fiduciary duties as a director or officer of
the Company or any subsidiary of the Company or limit or affect any actions
taken by the Stockholder in his capacity as an officer or director of the
Company or any subsidiary of the Company. The Stockholder has executed this
Agreement solely in his capacity as the record and/or beneficial holder of
Shares.

         9.12 Counterparts. This Agreement may be executed in any number of
counterparts, each of which will be deemed to be an original, but all of which
together will constitute one agreement.



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IN WITNESS WHEREOF, the parties have executed this Agreement to take effect as
of the date set forth above.



GEAC COMPUTER CORPORATION LIMITED

By: /s/ Paul D. Birch
   --------------------------------

Name: Paul D. Birch

Title: President and Chief Executive Officer



CONDUCTOR ACQUISITION CORP.

By: /s/ Paul D. Birch
   --------------------------------

Name: Paul D. Birch

Title: President and Chief Executive Officer


STOCKHOLDER

By: /s/ Dennis Ganster
   --------------------------------
     Dennis G. Ganster




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