<PAGE>   1
EXHIBIT 10.1



                       AMENDMENT NO. 1 TO CREDIT AGREEMENT

      Amendment No. 1 (this "Amendment"), dated as of September 28, 2000, to the
Credit Agreement, dated as of June 30, 1999, among The BISYS Group, Inc., the
Lenders party thereto, The Chase Manhattan Bank, Bank One, NA (formerly The
First National Bank of Chicago), First Union National Bank and Fleet National
Bank (formerly Fleet Bank, National Association), as co-agents thereunder, and
The Bank of New York, as Administrative Agent (as amended, supplemented or
otherwise modified, the "Credit Agreement").

                                    RECITALS

      A. Capitalized terms used herein which are not defined herein and which
are defined in the Credit Agreement shall have the same meanings as therein
defined.

      B. The Borrower has requested that the Administrative Agent agree to amend
the Credit Agreement upon the terms and conditions contained in this Amendment,
and the Administrative Agent is willing so to agree.

      Accordingly, in consideration of the Recitals and the covenants,
conditions and agreements hereinafter set forth, and for other good and valuable
consideration, the receipt and adequacy of which are hereby acknowledged, the
Borrower and the Administrative Agent hereby agree as follows:

      1. The definition of the term "Commitment" set forth in the Credit
Agreement is amended by deleting the amount "$200,000,000" and inserting the
amount "$300,000,000" in its place and stead.

      2. Schedule 2.1 to the Credit Agreement is amended and restated in its
entirety in the form of Attachment 1 hereto.

      3. Section 7.4(l) of the Credit Agreement is amended by deleting the
reference "subsection (g)" and inserting the reference "subsection (k)" in its
place and stead.

      4. If any Revolving Loan shall be outstanding immediately after giving
effect to paragraphs 1 and 2 hereof, then simultaneously with the effectiveness
of such paragraphs, the Lenders shall be deemed to have entered into a master
assignment and acceptance, substantially in the form of Exhibit A to the Credit
Agreement, pursuant to which they shall have sold and assigned to each other,
and purchased and assumed from each other, in each case without recourse, such
interests in their respective rights and obligations under the Credit Agreement
(including such interests in their respective participations in respect of the
Letters of Credit (including their respective LC Exposures) and the Swingline
Loans (including their respective Swingline Exposures), but excluding accrued
interest and fees to and excluding the Amendment Effective Date (as defined
below)) as shall be necessary to reflect proportionately the Commitments as
adjusted in accordance with paragraphs 1 and 2 hereof, and in connection with
such master assignment and acceptance, (a) each Lender shall, on the Amendment
Effective Date (as defined below), pay and/or receive from each other Lender (in
each case through the Administrative Agent, for the account of the applicable
Lender) such amounts as shall be necessary to appropriately reflect the
assignments contemplated by such master assignment and acceptance and (b) each
Lender may, as appropriate, treat the assignment of any Eurodollar Borrowing as
a prepayment thereof for purposes of Section 3.6. Notwithstanding anything to
the contrary herein or in any Loan Document, no fee shall be payable to the
Administrative Agent in connection with such master assignment and acceptance
pursuant to Section 10.4(b)(iii) of the Credit Agreement.

      5. Paragraphs 1 through 4 hereof shall not be effective until each of the
following conditions is satisfied (the date, if any, on which such conditions
shall have been satisfied being referred to herein as the "AMENDMENT EFFECTIVE
DATE"):

            (a) the Administrative Agent (or its counsel) shall have received
      from each of the Loan Parties and the Lenders either (i) a counterpart of
      this Amendment signed on behalf of such Person or (ii) written evidence
      satisfactory to the Administrative Agent (which may include telecopy
      transmission of a signed signature page of this Amendment) that such
      Person has signed a counterpart of this Amendment;


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<PAGE>   2


            (b) the Administrative Agent shall have received a favorable written
      opinion (addressed to the Credit Parties and dated the Amendment Effective
      Date) from Kevin J. Dell, Esq., Executive Vice President, Secretary and
      General Counsel of the Borrower, on behalf of the Borrower, substantially
      in the form of Attachment 2 hereto;

            (c) the Administrative Agent shall have received a certificate,
      dated the Amendment Effective Date and signed by the Secretary or
      Assistant Secretary of the Borrower (together with a signature guaranty
      reasonably satisfactory to the Administrative Agent with respect to such
      officer), (i) attaching true and correct copies of all resolutions,
      consents and other documents evidencing all necessary corporate action (in
      form and substance reasonably satisfactory to the Administrative Agent)
      taken by the Borrower to authorize this Amendment and the transactions
      contemplated hereby, (ii) certifying that, since July 1, 1999, neither the
      Borrower's Certificate of Incorporation nor the Borrower's By-Laws have
      been amended, supplemented or otherwise modified, (iii) setting forth the
      incumbency of the officers of the Borrower who may sign this Amendment and
      each agreement or other document executed or delivered in connection
      herewith, including therein a signature specimen of each such officer, and
      (iv) a certificate of good standing of the Secretary of State of the State
      of Delaware with respect to the Borrower;

            (d) the Administrative Agent shall have received all fees and other
      amounts due and payable on or prior to the Amendment Effective Date,
      including, to the extent invoiced, reimbursement or payment of all
      out-of-pocket expenses required to be reimbursed or paid by the Borrower
      under the Loan Documents; and

            (e) the Administrative Agent shall have received such other
      documentation and assurances as it shall reasonably request in connection
      with this Amendment and the transactions contemplated hereby.

      6. The Borrower hereby (i) reaffirms and admits the validity and
enforceability of each Loan Document and the respective obligations of the Loan
Parties thereunder, and agrees and admits that no Loan Party has any defense to
or offset against any such obligation, and (ii) represents and warrants that no
Default has occurred and is continuing and that all of the respective
representations and warranties of the Loan Parties contained in the Loan
Documents are true and correct.

      7. This Amendment may be executed in any number of counterparts, each of
which shall be an original and all of which shall constitute one agreement. It
shall not be necessary in making proof of this Amendment to produce or account
for more than one counterpart signed by the party to be charged.

      8. This Amendment is being delivered in and is intended to be performed in
the State of New York and shall be construed and enforceable in accordance with,
and be governed by, the laws of the State of New York.

      9. The Credit Agreement shall in all other respects remain in full force
and effect.


                           [SIGNATURE PAGES TO FOLLOW]



                                      -17-
<PAGE>   3


      IN WITNESS WHEREOF, the parties hereto have caused this Amendment No. 1 to
be duly executed and delivered by their proper and duly authorized officers as
of the day and year first above written.


THE BISYS GROUP, INC.


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------

THE BANK OF NEW YORK, individually and as
Administrative Agent



By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



CONSENTED AND AGREED TO BY:
THE CHASE MANHATTAN BANK


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



CONSENTED AND AGREED TO BY:
BANK ONE, NA (FORMERLY THE FIRST
NATIONAL BANK OF CHICAGO)


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



CONSENTED AND AGREED TO BY:
FIRST UNION NATIONAL BANK


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



CONSENTED AND AGREED TO BY:
FLEET NATIONAL BANK (FORMERLY FLEET BANK,
NATIONAL ASSOCIATION)


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



CONSENTED AND AGREED TO BY:
PNC BANK, NATIONAL ASSOCIATION


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



CONSENTED AND AGREED TO BY:
SUNTRUST BANK


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



CONSENTED AND AGREED TO BY:
WACHOVIA BANK, N.A.


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



CONSENTED AND AGREED TO BY:
THE BANK OF NOVA SCOTIA


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



CONSENTED AND AGREED TO BY:
BISYS FUND SERVICES OHIO, INC.
BISYS FUND SERVICES, INC.
BISYS INSURANCE SERVICES, INC.
BISYS, INC.
BISYS DOCUMENT SOLUTIONS, INC.
BISYS EDUCATION SERVICES, INC.
POTOMAC INSURANCE MARKETING GROUP, INC.
PICTORIAL, INC.

AS TO EACH OF THE FOREGOING:


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



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<PAGE>   4


BISYS FUND SERVICES LIMITED PARTNERSHIP
By:  BISYS FUND SERVICES, INC.,
      General Partner


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



BISYS PLAN SERVICES LP
By: BPS (GP) INC., General Partner


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



CONSENTED AND AGREED TO BY:
BISYS INFORMATION SOLUTIONS L.P.
By: BISYS, INC., General Partner


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



BISYS DOCUMENT SOLUTIONS, L.P.
By: BISYS DOCUMENT SOLUTIONS, INC.,
     General Partner


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------



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