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                                  UNITED STATES

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                   ----------

                                  FORM 10-Q/A

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

                  For the Quarterly Period Ended June 30, 1997

                                       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 0-20095


                                   STAC, INC.
             (Exact name of registrant as specified in its charter)


                   DELAWARE                                  95-3825313
       (State or other jurisdiction of                    (I.R.S. Employer
       incorporation or organization)                    Identification No.)


            12636 High Bluff Drive, San Diego, California 92130-2093
           (Address of principal executive office, including zip code)

                                 (619) 794-4300
              (Registrant's telephone number, including area code)


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
                                 -----     -----

Indicate the number of shares outstanding of each of the registrant's classes of
common stock as of June 30, 1997.

Common Stock, par value $.001 per share                        30,807,088 shares



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the result that significant sales of Replica could fail to materialize, or
products similar to Replica could be successfully introduced to resellers by the
Company's competitors. In addition, Microsoft's current operating systems
incorporate back-up functionality and future operating systems are expected to
include some disaster recovery functionality. Also, Replica is being introduced
into sophisticated server environments and, while the Company has invested
significant resources in testing Replica under a variety of conditions,
configurations and circumstances, there are likely to be environments which have
not been anticipated for which additional development of Replica will be
necessary.

        The Company's license agreement with IBM Corporation grants IBM the
right to implement, but not sublicense, the Company's patented data compression
technology in IBM hardware and software products. Also, microprocessor and chip
set suppliers, customers and others could seek to expand their product offerings
by designing and selling products using competitive data compression, or could
rely on software implementations of data compression and data encryption, or use
other technologies, any of which could render obsolete or adversely affect sales
of Hi/fn's semiconductor and software products.

        Stock Price Volatility. Due to the factors noted above, the Company's
future earnings and stock price may be subject to significant volatility,
particularly on a quarterly basis. Any shortfall in earnings from levels
expected by securities analysts could have an immediate and significant adverse
effect on the trading price of the Company's common stock in any given period.
Shortfalls could be caused by shortfalls in revenues, timing of the receipt of
technology license fees, and/or increased levels of expenditures. Additionally,
the Company participates in a highly dynamic industry, which often results in
significant volatility of the Company's stock price.

LIQUIDITY AND CAPITAL RESOURCES

        The Company's cash and marketable securities increased by $3.7 million
to $69.1 million at June 30, 1997 from that at September 30, 1996. The increase
was primarily attributable to cash generated from operations. Working capital
increased by $4.1 million to $72.6 million at June 30, 1997 from that at
September 30, 1996.

        During the December 1995 quarter the Company paid $0.2 million in
dividends on its Series A Preferred Stock. The obligation to pay the preferred
dividend terminated when the preferred stock was converted to common stock in
November 1995.

   
        On August 13, 1997, the Company announced a tender offer for up to 6.0
million shares of its common stock at prices to be determined by shareholders in
the range of $4.75 to $5.50 per share. If the maximum number of shares is
tendered at the maximum price in the range, the Company will expend $33.0
million plus expenses to satisfy the offer. The tender offer replaces the $20.0
million share repurchase program approved by the Company's Board of Directors in
June 1997.
    

        The Company believes that, notwithstanding the completion of the above
tender offer, existing cash balances and funds provided by operations will be
sufficient to finance its working capital requirements for the foreseeable
future.




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                                    Signature



Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this report to be signed by the undersigned thereunto
duly authorized.





                                                     Stac, Inc.
                                        ----------------------------------------



Date:  August 18, 1997
                                                   John R. Witzel
                                        ----------------------------------------
                                                   John R. Witzel
                                             Vice President of Finance and
                                                Chief Financial Officer






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