After you install a custom Cryptographic Service Provider (CSP) on a computer that is running Windows XP, you cannot encrypt Office Open XML (OOXML) files or open existing encrypted OOXML files in Microsoft Office 2010. 


To resolve this issue, apply the following update:

2596996 Description of the Office 2010 hotfix package (x86 Mso-x-none.msp, x64 Mso-x-none.msp): December 13, 2011

Registry key information

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756 How to back up and restore the registry in WindowsAfter you install the hotfix package, follow these steps to enable the hotfix:

  1. Click Start, click Run, type regedit in the Open box, and then click OK.

  2. Locate and then select the following registry subkey:

  3. On the Edit menu, point to New, and then click Key.

  4. Type Security, and then press ENTER.

  5. Locate and then select the following registry subkey:


  6. On the Edit menu, point to New, and then click String value.

  7. Type DeprecatedProviders, and then press ENTER.

  8. In the Details pane, right-click DeprecatedProviders, and then click Modify.

  9. In the Value data box, type The Custom CSP Name, and then click OK.

  10. Exit Registry Editor.

Note You can find the custom CSP name by navigating to the following registry location:



Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

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