[Quantum Letterhead]

November 8, 2012

Mr. Jon W. Gacek
[address]

                  Re:         Amendment to Offer Letter dated as of March 31,
2011

Dear Jon,

     As you may recall, your offer letter with Quantum Corporation (the
“Company”) dated March 31, 2011 (the “Offer Letter”), provides for severance
benefits to be paid to you if your employment is involuntarily terminated by the
Company other than for “cause” and a “Change in Control” (as such terms are
described in the Offer Letter) has not occurred (the “Severance Benefits”).

     The Offer Letter is intended to comply with Section 409A of the Internal
Revenue Code of 1986, as amended and the final Treasury Regulations and any
guidance promulgated thereunder (collectively, “Section 409A”), so that the
Severance Benefits are not subject to any tax, interest or penalties under
Section 409A. For purposes of better complying with Section 409A, this letter
(the “Amendment”) modifies the terms of the Offer Letter by including the
following additional terms and conditions:

 * The separation agreement and general release that is required to be executed
   in exchange for the Severance Benefits must become effective within 60 days
   after the termination of your employment. Your Severance Benefits will be
   paid in a single lump sum on the 60th day after you have a “separation from
   service” as defined in Section 409A.
    
 * References to your termination of employment with respect to any six-month
   delay required by Section 409A will mean a “separation from service” as
   defined in Section 409A.

     Except as provided above, the Offer Letter remains in full force and
effect. Please acknowledge your agreement by countersigning below and returning
your countersignature to me at your earliest convenience.

[Signature page follows.]

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Sincerely,       /s/ Shawn D. Hall   Shawn D. Hall Senior Vice President,
General Counsel and Secretary   Quantum Corporation

Agreed and Accepted November 8, 2012

/s/ Jon W. Gacek   Jon W. Gacek

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