Exhibit 8.1


                [HELLER EHRMAN WHITE & MCAULIFFE LLP LETTERHEAD]


February 6, 2003


Geac Computer Corporation Limited
11 Allstate Parkway, Suite 300
Markham, Ontario, L3R 9T8
CANADA
Attn: Mr. Paul Birch

Ladies and Gentlemen:

      This opinion is being delivered pursuant to the Form F-4 Registration
Statement filed on February 6, 2003, in connection with the merger pursuant to
the Amended and Restated Agreement and Plan of Merger (the "Agreement"), dated
as of February 4, 2003, by and among Geac Computer Corporation Limited, a
corporation governed by the Canada Business Corporations Act ("Geac"), Cage
Acquisition Inc., a Delaware corporation all of the common stock of which is
owned by Geac ("Cage"), Geac Computers, Inc., a Missouri corporation ("GCI") and
Extensity, Inc., a Delaware corporation ("Extensity"). Except as otherwise
provided, capitalized terms used but not defined herein shall have the meanings
set forth in the Agreement. All "section" references, unless otherwise
indicated, are to the Internal Revenue Code of 1986, as amended (the "Code").

      We have acted as special U.S. tax counsel to Geac, GCI and Cage in
connection with the Merger. As such, and for the purpose of rendering this
opinion, we have examined, and are relying upon (without any independent
investigation or review thereof) the truth and accuracy at all relevant times
(including without limitation the Effective Time) of, the statements, covenants,
representations, and warranties contained in the following documents (including
all exhibits and schedules attached thereto):

      (a) the Agreement;

      (b) the Registration Statement;

      (c) a representation letter from Geac as to certain matters;

      (d) the Amended and Restated Certificate of Incorporation of Cage and the
terms of the preferred stock issued by Cage to CIBC WMC Inc. and


                                               Geac Computer Corporation Limited
                                               February 6, 2003
                                               Page 2


      (e) such other instruments and documents related to the formation,
organization, and operation of Geac, GCI and Cage, and related to the
consummation of the Merger and the other transactions contemplated by the
Agreement as we have deemed necessary or appropriate.

      In connection with rendering this opinion, we have assumed (without any
independent investigation or review thereof) that:

      (a) Original documents submitted to us (including signatures thereto) are
authentic, documents submitted to us as copies conform to the original
documents, and all such documents have been (or will be by the Effective Time)
duly and validly executed and delivered where due execution and delivery are a
prerequisite to the effectiveness thereof;

      (b) The representations, warranties, and statements made or agreed to by
Geac, GCI, Cage and Extensity, in connection with the Merger, set forth or
described in the Agreement (including the exhibits thereto), the representation
letter from Geac and the Registration Statement, are true and accurate at all
relevant times;

      (c) All covenants contained in the Agreement (including exhibits thereto)
and the Registration Statement are performed without waiver or breach of any
material provision thereof;

      (d) The Merger and the ownership of GCI, Cage and Extensity will be
reported by Geac, GCI, Cage and Extensity on their respective United States and
Canadian federal income tax returns in a manner consistent with the opinion set
forth below;

      (e) Any representation or statement qualified with reference to the
"knowledge" or intention of a person is correct without such qualification; and

      (f) The Registration Statement and the Agreement reflect all the material
facts relating to the Merger, Geac, GCI, Cage and Extensity.

      Based on the above and subject to the limitations, qualifications, and
assumptions set forth herein, we are of the opinion that for United States
federal income tax purposes if more than 20% of the merger consideration paid by
Geac and GCI is paid in cash as a result of Extensity stockholders failing to
elect to receive shares of Geac, the Merger will be treated for United States
income tax purposes as a taxable purchase of the stock of Extensity by Geac, and
the sale of such stock by the stockholders of Extensity, and not as a
"reorganization" as defined in Section 368(a) of the Code, and if less than 20%
of the merger consideration paid by Geac and GCI is paid in cash, the Merger
should be treated for United States income tax purposes as a taxable purchase of
the stock of Extensity by




                                               Geac Computer Corporation Limited
                                               February 6, 2003
                                               Page 3


Geac and the sale of such stock by the stockholders of Extensity, and not as a
"reorganization" as defined in Section 368(a) of the Code.

      This opinion is limited to the United States federal income tax
characterization of the Merger and does not address the various state, local, or
non-U.S. tax consequences that may result from the Merger or the other
transactions contemplated by the Agreement. In addition, no opinion is expressed
as to any United States federal income tax consequence of the Merger or the
other transactions contemplated by the Agreement except as specifically set
forth herein. This opinion is being furnished to you in connection with the
Merger and may not be used or relied upon for any other purpose except as
provided below.

      To the extent that any of the representations, warranties, statements and
assumptions material to our opinion and upon which we have relied are not
accurate and complete in all material respects at all relevant times, our
opinion could be adversely affected and should not be relied upon. Finally, the
opinion set forth above is subject to all of the exceptions, conditions,
qualifications, limitations, assumptions and caveats set forth in the ABA Legal
Opinion Accord.

      This opinion is not binding on the Internal Revenue Service or any court
of law, administrative agency or other governmental body and represents only our
judgment as to the likely outcome if the federal income tax consequences of the
Merger were properly presented to a court of competent jurisdiction. Our
conclusions are based on the Code, existing judicial decisions, administrative
regulations and published rulings as in effect on the date hereof. No assurance
can be given that future legislative, judicial or administrative changes or
interpretations will not adversely affect the accuracy of our conclusions.
Nevertheless, by rendering this opinion, we undertake no responsibility to
advise you of any new developments in the application or interpretation of the
federal income tax laws.

      We consent to the reference to our firm under the caption "Material United
States Federal Income Tax Consequences" included in the Registration Statement
and to the reproduction and filing of this opinion as an exhibit to the
Registration Statement.

                                    Very truly yours,

                                    /s/ Heller Ehrman White & McAuliffe LLP