Article ID: 2597997 - View products that this article applies to.
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 encrypted OOXML files in the 2007 Microsoft Office system.
To resolve this issue, apply the following update:
(https://support.microsoft.com/kb/2598030/ )Description of the 2007 Office system hotfix package (Mso-x-none.msp): February 28, 2012
Registry key informationImportant 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:
322756After you install the hotfix package, follow these steps to enable the hotfix:
(https://support.microsoft.com/kb/322756/ )How to back up and restore the registry in Windows
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Article ID: 2597997 - Last Review: February 28, 2012 - Revision: 1.0