FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  Dalton Stephen P
 2. Date of Event Requiring Statement (Month/Day/Year)
03/29/2007		 3. Issuer Name and Ticker or Trading Symbol
QUANTUM CORP /DE/ [QTM]
(Last)
(First)
(Middle)
1650 TECHNOLOGY DRIVE, SUITE 700		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
SVP, Tiered Storage Solutions
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

SAN JOSE, CA 95110		 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Stock (1) 20,000
D
 

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Non-qualified stock option 02/01/2006(2) 03/22/2012 Common Stock (3) 150,000 $ 2.76 D  
Non-qualified stock option 07/01/2005(4) 05/31/2012 Common Stock (3) 50,000 $ 2.62 D  
Non-qualified stock option 11/16/2007(2) 11/16/2013 Common Stock (3) 150,000 $ 2.38 D  
Restricted Stock Units (6) 08/22/2007(5)   (5) Common Stock (6) 80,000 $ 0 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Dalton Stephen P
1650 TECHNOLOGY DRIVE
SUITE 700
SAN JOSE, CA 95110		       SVP, Tiered Storage Solutions  

Signatures

Shawn Hall 04/06/2007
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Restricted Stock Award granted on October 25, 2005 under Rule 16b-3. Restricted stock will vest 25% annually over four years beginning on October 1, 2006.
(2) Stock option vests 25% on the first anniversary and monthly thereafter at a rate of 1/48th per month for the remaining three years.
(3) Right to buy under Rule 16b-3 plan.
(4) Stock option vests monthly in equal installments over 4 years.
(5) Restricted Stock Units will vest over a period of two years, as follows: the first 50% will vest on August 22, 2007 and the remaining 50% on August 22, 2008.
(6) Restricted Stock Units convert to shares of Common Stock on a 1-for-1 basis.

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