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                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON D.C. 20549



                                  FORM 10-Q/A

(Mark One)

[x]      QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES
         EXCHANGE ACT OF 1934

                For the quarterly period ended September 30, 1998

                                       OR

[ ]      TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES
         EXCHANGE ACT OF 1934

                        For the transition period from to
                        Commission File Number 000-27900


                                    ISOCOR(R)
             (Exact name of Registrant as Specified in Its Charter)

          California                                       95-4310259
(State or Other Jurisdiction of                         (I.R.S. Employer 
Incorporation or Organization)                         Identification No.)

3420 Ocean Park Blvd., Santa Monica, CA                     90405
(Address of principal executive offices)                  (Zip Code)


       Registrant's telephone number, including area code: (310) 581-8100


         Indicate by check mark whether the Registrant: (1) has filed all
reports required to be filed by Section 13 or 15 (d) of the Securities Exchange
Act of 1934 during the preceding 12 months (or for such shorter period that the
Registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.

                                 Yes [X] No [ ]

            9,822,225 Shares of Common Stock of the Registrant were outstanding
as of September 30, 1998

The undersigned is hereby filing Exhibit 10.21 to its Quarterly Report on Form 
10-Q for the quarter ended September 30, 1998, which exhibit was previously 
omitted.



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PART II Other Information

Item 6. - Exhibits and Reports on Form 8-K

     (a) The following exhibits are filed as part of this Quarterly Report on
Form 10-Q:

         10.21+  Software License Agreement between the Registrant and
                 Netscape Communications Corporation dated September 30, 1998

         27.1    Financial Data Schedule.

         + Confidential Treatment Requested.

     (b) No reports on Form 8-K have been filed during the quarter for which
this report has been filed.



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                                    SIGNATURE

         Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report on Form 10-Q/A to be signed on its
behalf by Janine M. Bushman, thereunto duly authorized to sign on behalf of the
registrant and as the principal financial officer thereof.

                                        ISOCOR


Date: January 27, 1999                  By: /s/JANINE M. BUSHMAN 
                                            ------------------------------------
                                            Janine M. Bushman, Vice President,
                                            Finance and Administration, and 
                                            Chief Financial Officer (Principal 
                                            Financial and Accounting Officer)



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                               INDEX TO EXHIBITS


<TABLE>
<CAPTION>
Exhibit 
Number                        Exhibits                                    Page
-------------------------------------------------------------------------------
<S>            <C>                                                        <C>
10.21          Software License Agreement between the Registrant
               and Netscape Communications Corporation dated
               September 30, 1998 ........................................  5
27.1           Financial Data Schedule ................................... 36
</TABLE>



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