QUANTUM CORP /DE/

PROXY VOTING INSTRUCTIONS Please have your 11-diait control number ready when voting by Internet or Telephone. Vote Your Proxy on the internet: Go to https://aalvote.com/QMCO Have your proxy card available when you access the above website. Follow the prompts to vote your shares. Vote Your Proxy by Phone: Call 1 846 804 9616 Use any touch-tone telephone to vote your proxy. Hove your proxy card available when you col. Follow the voting instructions to vote your shares. Vote Your Proxy by Mail: Mark, sign, and date your proxy card, then detach it and return it in the postage-paid envelope provided. NAME & ADDRESS HEREAs a shareholder of Quantum Corporation, you have the option of voting your shares electronically through the Internet or by telephone, eliminating the need to return the proxy card. Your electronic or telephonic vote authorizes the named proxies to vote your shares in the same manner as if you marked, signed, dated, and returned the proxy card. Votes submitted electronically over the Internet or by telephone must be received by 11:59 p.m.. Eastern Time, on [DATE], 2025. PLEASE DETACH ALONG PERFORATE line AND MAiL IN THE envelope PROVIDed QUANTUM CORPORATION ANNUAL MEETING OF SHAREHOLDERS [DATE], 2025 AT [TIME] AM.. PACIRC TIME THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD Of DIRECTORS Of QUANTUM CORPORATION The undersigned, revoking all prior proxies heretofore granted hereby appoints Hugues Meyrath, Lewis W. Moorehead, and Tara lges and each of them, as proxies, each with the power to appoint his or her substitute, on behalf and in the name of the undersigned, to represent and to vote all of the shares of common stock of Quantum Corporation that the undersigned is entitled to vote of the Annual Meeting of Shareholders to be held at [time], Pacific Time, on [date], 2025 and any adjournment or postponement thereof. The Annual Meeting of Shareholders will be held virtually, in order to attend the meeting you must register of web.viewproxy.com/QMCO/2025 by 11:59 pm, Eastern Time, on [date], 2025. On the day of the Annual Meeting and at any adjournment or postponement thereof, If you have property registered, you may enter the meeting by clicking on the link provided and using the password you received via email in your registration confirmation. This proxy, when property executed, will be voted in the manner directed herein by the undersigned. Where no direction is given, the shares represented by this proxy will be voted FOR each nominee in Proposal 1 and for Proposals 2,3,4,5,6,7 and 8 in accordance with the Board of Directors’ recommendations. In their discretion, the proxies are authorized to vote upon and transact such other business as may property come before the Annual Meeting and any adjournments and postponements thereof. Unless you specifically instruct otherwise, this proxy conifers discretionary authority to cumulate votes for any or all of the nominees for election of directors except for nominees for whom you have voted “Against” or “Abstain”, in accordance with the instruction of the Board of Directors. At the Annual Meeting, unless you specifically instruct otherwise the Board of Directors will instruct the proxy holders to cast the votes as to which voting authority has been granted so as to provide for the election of the maximum number of the Company’s director nominees, and will provide instructions as to the order of priority of our nominees in the event that fewer than all of our nominees are elected. If any nominee nomad on the reverse side for good cause will not serve or is unable to serve as a director, the persons named as proxies shall have the authority to vote for any other person who may be nominated of the instruction and discretion of the Board of Directors or an authorized committee thereof. NAME & ADDRESS HERE CONTROL NUMBER Address Change: (If you noted anу Address Changes above, please mark box.) Cumulative votting instructions mark the corresponding box on the reverse side If you noted cumulative votting instructions please check the corresponding box on the reverse side. Note: please sign extactly as name(s) appear(s) hereon. When signing as attorney executor, administrator or other fiduciary please give full title such as joint owner should each sign personally if a corporation limited locality company or partnership please sign in full corporate limited liability company or partnership named by authorised officer or person Signature Date Title Signature (Joint Owners)

Notice of Meeting and Important Notice Regarding the Availability of Proxy Materials for the Annual Meeting of Shareholders to be held on [Date], 2025: The Notice, Proxy Statement, and Annual Report on Form 10-K are available at: web.viewproxy.com/QMCO/2025 PLEASE DETACH ALONG PERFORATED line AND MAiL IN THE ENVELOPE PROVIDED The shares represented by this proxy, when property executed, will be voted in the manner directed herein by the undersigned. Where no direction is given, the shares represented by this proxy will be voted FOR each nominee in Proposal 1 and FOR Proposals 2. 3, 4, S, 6, 7. And 8. In their discretion, the proxies are authorized to vote upon and transact such other business as may properly come before the Annual Meeting and any adjournments and postponements thereof. Please mark your votes like this Propose! 1: Election of seven directors to serve for a term expiring at the 2026 annual meeting of shareholders or until their successors are duty qualified and elected. ELECTION or DIRECTORS: FOR AGAINST ABSTAIN(1) Hugues Meyrath (2) Tony J Blevins (3) James C. Clancy (4)John A. Hchlhorn (5) Donald J. Jaworskj (6) John R. Tracy (7) Yue Zhou (Emfty) While Unless otherwise specified, this proxy authorizes the proxies named on the reverse side to cumulate votes that the undersigned is enticed to cast at the Annual Meeting in connection with the election of directors and allocate them among d rector nominees for which you do not vote ‘Against’’ or ‘Abstain.” To provide specific directions with regard to cumulative voting, including to direct that the proxy holders cumulate votes with respect to a specific Board nominee or nominees as explained in the proxy statement or to withhold authority to cumulate votes, mark the box to the right and rite your instructions on the reverse side. If you wish to direct that the proxy holders cumulate votes with respect to a specific Board nominee or nominees. Please indicate the name|s| and number of votes to be given to such Board nominee- You may not cumulate votes * Against” a nominee. FOR AGAINST abstain Proposal 2: Approval of. For purposes of complying with Nasdaq listing rule 5425, the issuance of shares of common stock to Dialectic Technology SPV LLC in connection with the exchange of certain outstanding term loans for one or more senior secured convertible notes. FOR AGAINST abstain Propose 3: Approval of. For purposes of complying with Nasdaq listing rule 5635, the issuance of shares of common stock to Dialectic Technology SPV LLC upon the conversion of any additional senior secured convertible notes that may be issued beyond those contemplated by the debt exchange described in Proposal 2. FOR AGAINST abstain Propose* 4: Approval of. For purposes of complying with Nasdaq listing rule 5635, the issuance of shares of common stock to Dialectic Technology SPV LLC that may become issuable under its warrant as a result of anti-dilution adjustments. FOR AGAINST abstain Proposed 5: Approval of an amendment and restatement of the Quantum Corporation 2023 Long-Term incentive Plan to increase the number of shares of common stock reserved for issuance thereunder by 1,400,000 shores and remove the individual annual award limits for employees or consultants. FOR AGAINST abstain Propose* 6: Approval of the compensation of our named executive officers, on a non-binding advisor/ basis. FOR AGAINST abstain Propose* 7: Ratification of the appointment of cohnreznick LLP as our independent registered pubic accounting firm for the year ending March 31. 2026. FOR AGAINST abstain Propose* 8: Approval of the adjournment of the Annual Meeting to a later dote, if necessary or appropriate. FOR AGAINST abstain