The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be 'filed' for the purpose of Section 18 of the Securities Exchange Act of 1934 ('Act') or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

Wells Fargo & Company (the "Parent Company") may be deemed to beneficially own 14,604,918 shares of the common stock, par value $0.01 ("Common Stock"), of CommVault Systems, Inc., consisting of 14,594,653 shares of Common Stock that Wells Fargo Bank, N.A. (the "Bank"), a subsidiary of the Parent Company, may be deemed to beneficially own as described below and 27,058 shares of Common Stock that other Parent Company subsidiaries may be deemed to beneficially own (see Exhibit B). Of the 14,594,653 shares of Common Stock that the Bank may be deemed to beneficially own, 14,577,860 shares are subject to a Voting Trust Agreement, dated as of September 21, 2006 (the "Agreement"), among Wells Fargo Bank, N.A.(the Bank), and Credit Suisse Securities (USA) LLC and certain of its affiliates.

         Under the Agreement, the shares have been deposited into a voting trust and are voted by the Bank in accordance with the Agreement. The Agreement requires that the Bank cause the shares of Common Stock subject to the Agreement to be represented at all CommVault stockholder meetings for purposes of determining a quorum, but the Bank is not required to vote the shares on any matter and any determination whether to vote the shares is required by the Agreement to be made by the Bank without consultation with Credit Suisse Securities (USA) LLC and its affiliates. If, however, the Bank votes the shares on any matter subject to a stockholder vote, including proposals involving the election of directors, change of control and other significant corporate transactions, the shares will be voted in the same proportion as votes cast “for” or “against” those proposals by other CommVault stockholders.
     
         Holders of shares of Common Stock subject to the Agreement will retain the right to receive any dividends or distributions paid on the Common Stock. In order for a holder to cause shares covered by the Agreement to be distributed or transfered, the transfer must be deemed an “eligible transfer” under the Agreement, or such transfer must be in connection with a tender offer to purchase all of the outstanding shares of Common Stock. Generally, an eligible transfer under the Agreement is a transfer of shares that would not (i) subject to certain normal trading activity and customer account exceptions cause the aggregate number of shares of Common Stock held outside of the voting trust by Credit Suisse Securities (USA) LLC and its affiliates to equal or exceed 5% of the Common Stock then outstanding or (ii) cause the entity receiving the shares to be an affiliate of CommVault. The Agreement also permits the parties to the Agreement to make distributions-in-kind of shares of Common Stock subject to the Agreement upon the satisfaction of specified requirements.

         The Agreement will terminate upon the earliest of:
             

• September 21, 2016;             

• the written election of Credit Suisse First Boston Private Equity, Inc., an affiliate of Credit Suisse Securities (USA) LLC, Credit Suisse Securities (USA) LLC or the holders of the majority of the shares of Common Stock subject to the Agreement and the satisfaction of specified requirements; or             

• the transfer of all of the shares of Common Stock subject to the Agreement in a matter permitted thereunder.

         The Agreement provides Credit Suisse First Boston Private Equity, Inc., Credit Suisse Securities (USA) LLC and the holders of a majority of the shares of Common Stock subject to the Agreement with the right to terminate the Agreement subject to the satisfaction of specified requirements, including that, immediately after giving effect to such termination, Credit Suisse First Boston Private Equity, Inc. and its affiliates will not be affiliates of CommVault within the meaning of Rule 144 of the Securities Act of 1933.

         The foregoing discussion of the Agreement is qualified in its entirety by reference to the Agreement, which is filed as Attachment A hereto and incorporated herein by reference.

Attachment A: Voting Trust Agreement, dated as of September 21, 2006, among Wells Fargo Bank, N.A. and Credit Suisse Securities (USA) LLC and certain of its affiliates.

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