Article ID: 967732 - View products that this article applies to.
When you open a Microsoft Office Word document or a Microsoft Office Excel workbook that has a digital signature, you cannot edit the Word document or the Excel workbook. Additionally, the "Invalid signature" indication appears even if the signature was created during the period when a certificate was valid.
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:
(https://support.microsoft.com/kb/322756/ )How to back up and restore the registry in Windows
To open an Office file without displaying the "Invalid signature" indication, install the 2007 Office system hotfix package that is dated February 24, 2009, and then configure the
IgnoreExpiredCertregistry entry to enable the hotfix. To do this, follow these steps:
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Article ID: 967732 - Last Review: March 3, 2009 - Revision: 1.0