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                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                   ----------

                                   FORM 8-K/A

                                 CURRENT REPORT

                     PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934


       Date of report (Date of earliest event reported): February 4, 2000


                          Concord Communications, Inc.
         ---------------------------------------------------------------
               (Exact Name of Registrant as Specified in Charter)



      Massachusetts                  0-23067                    04-2710876
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(State or Other Jurisdiction       (Commission                 (IRS Employer
     of Incorporation)             File Number)             Identification No.)


600 Nickerson Road, Marlboro, Massachusetts                         01752
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(Address of Principal Executive Offices)                         (Zip Code)



       Registrant's telephone number, including area code: (508) 460-4646
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ITEM 2.  ACQUISITION OR DISPOSITION OF ASSETS

      As previously disclosed in a Current Report on Form 8-K filed on February
10, 2000, on February 4, 2000, Concord Communications, Inc. ("Concord")
completed its acquisition of all of the capital stock of FirstSense Software,
Inc., a Delaware corporation ("FirstSense"), by means of a merger ("Merger") of
F Acquisition Corp. ("Merger Sub"), a Delaware corporation and wholly owned
subsidiary of Concord with and into FirstSense, pursuant to the Agreement and
Plan of Reorganization dated as of January 20, 2000 by and among Concord, Merger
Sub and FirstSense. As a result of the Merger, FirstSense became a wholly owned
subsidiary of Concord and will continue to operate as a wholly owned subsidiary
of Concord. The Merger was effected by the filing of a Certificate of Merger
with the Secretary of State of Delaware on February 4, 2000. FirstSense is a
provider of applications performance and service level management software
designed for distributed applications, including packaged, custom and e-business
applications.

      The financial statements of FirstSense relating to the acquisition
required to be filed in connection with the acquisition pursuant to Items 7(a)
and 7(b) of Form 8-K, are included herewith.

ITEM 7.  FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND EXHIBITS.

      (a) Financial Statements of Business Acquired.
          ------------------------------------------

          This Amendment to Current Report on Form 8-K of Concord
          Communications, Inc. (the "Company") is being filed to disclose the
          audited balance sheets of FirstSense Software, Inc. as of December 31,
          1999 and 1998 and the related audited statements of operations,
          stockholders' (deficit) equity and cash flows for each of the
          years in the three year period ended December 31, 1999, 1998 and 1997,
          with accompanying notes, which are attached as Exhibit 99.3.

      (b) Pro Forma Financial Information.
          --------------------------------

          The following unaudited pro forma consolidated statements of
          operations for the year ended December 31, 1999 and unaudited pro
          forma consolidated balance sheet as of December 31, 1999, which are
          attached as Exhibit 99.4, give effect to the Merger described in Item
          2. The unaudited pro forma information is presented for illustrative
          purposes only and may not be indicative of the results that would have
          been obtained had the transaction actually occurred on the dates
          assumed, nor is it necessarily indicative of the future consolidated
          results of operations.

      (c) Exhibits.

     EXHIBIT NO.          DESCRIPTION
     -----------          -----------
             2.1          Agreement and Plan of Reorganization dated as of
                          January 20, 2000 by and among Concord Communications,
                          Inc., F Acquisition Corp., and FirstSense Software,
                          Inc. (filed as Exhibit 2.1 to the original Report on
                          Form 8-K dated February 4, 2000 and filed with the
                          Commission on February 10, 2000 and hereby
                          incorporated by reference).


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     EXHIBIT NO.          DESCRIPTION
     -----------          -----------
              23.1        Consent of Independent Public Accountants (filed
                          herewith).

              99.1        Registration Rights Agreement dated as of February 4,
                          2000 by and among Concord Communications, Inc. and
                          Timothy Barrows, as Securityholder Agent (filed as
                          Exhibit 99.1 to the original Report on Form 8-K dated
                          February 4, 2000 and filed with the Commission on
                          February 10, 2000 and hereby incorporated by
                          reference).

              99.2        Press Release dated February 7, 2000 (filed as Exhibit
                          99.2 to the original Report on Form 8-K dated February
                          4, 2000 and filed with the Commission on February 10,
                          2000 and hereby incorporated by reference).

              99.3        The following audited financial statements of
                          FirstSense Software, Inc. (filed herewith):

                          Independent Auditors' Report

                          Balance Sheets as of December 31, 1999 and 1998

                          Statements of Operations for the years ended December
                          31, 1999, 1998 and 1997

                          Statements of Stockholders' (Deficit) Equity for the
                          years ended December 31, 1999, 1998 and 1997

                          Statements of Cash Flows for the years ended December
                          31, 1999, 1998 and 1997

                          Notes to the Financial Statements

              99.4        The following pro forma financial information of
                          Concord Communications, Inc. and FirstSense Software,
                          Inc. (filed herewith):

                          Unaudited Consolidated Statements of Operations for
                          the years ended December 31, 1999 and 1998

                          Unaudited Consolidated Balance Sheet as of December
                          31, 1999


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                                   SIGNATURES


      Pursuant to the requirements of the Securities Exchange Act of 1934, the
Company has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.


                                        CONCORD COMMUNICATIONS, INC.



Dated:  April 19, 2000
                                        By:  /s/ Melissa H. Cruz
                                             -------------------
                                             Melissa H. Cruz
                                             Executive Vice President of Finance
                                             and Chief Financial Officer


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                                  EXHIBIT INDEX


 EXHIBIT NO.      DESCRIPTION
 -----------      -----------

         2.1      Agreement and Plan of Reorganization dated as of January 20,
                  2000 by and among Concord Communications, Inc., F Acquisition
                  Corp., and FirstSense Software, Inc. (filed as Exhibit 2.1 to
                  the original Report on Form 8-K dated February 4, 2000 and
                  filed with the Commission on February 10, 2000 and hereby
                  incorporated by reference).

         23.1     Consent of Independent Public Accountants (filed herewith).

         99.1     Registration Rights Agreement dated as of February 4, 2000 by
                  and among Concord Communications, Inc. and Timothy Barrows, as
                  Securityholder Agent (filed as Exhibit 99.1 to the original
                  Report on Form 8-K dated February 4, 2000 and filed with the
                  Commission on February 10, 2000 and hereby incorporated by
                  reference).

         99.2     Press Release dated February 7, 2000 (filed as Exhibit 99.2 to
                  the original Report on Form 8-K dated February 4, 2000 and
                  filed with the Commission on February 10, 2000 and hereby
                  incorporated by reference).

         99.3     The following audited financial statements of FirstSense
                  Software, Inc. (filed herewith):

                  Independent Auditors' Report

                  Balance Sheets as of December 31, 1999 and 1998

                  Statements of Operations for the years ended December 31,
                  1999, 1998 and 1997

                  Statements of Stockholders' (Deficit) Equity for the years
                  ended December 31, 1999, 1998 and 1997

                  Statements of Cash Flows for the years ended December 31,
                  1999, 1998 and 1997

                  Notes to the Financial Statements


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 EXHIBIT NO.      DESCRIPTION
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         99.4     The following pro forma consolidated financial information of
                  Concord Communications, Inc. and FirstSense Software, Inc.
                  (filed herewith):

                  Unaudited Pro Forma Consolidated Statements of Operations for
                  the years ended December 31, 1999 and 1998

                  Unaudited Pro Forma Consolidated Balance Sheet as of December
                  31, 1999


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