Users receive a "your digital ID name cannot be found by the underlying security system" error message in Exchange 2000 Server

When a user tries to open a digitally signed e-mail message, the user may receive the following error message: Additionally, the e-mail message may be truncated.

This problem may occur when all the following conditions are true:

• The e-mail message is larger than 64 kilobytes (KB).
• The recipient's mailbox is located on a computer that is running Microsoft Exchange 2000 Server, and the computer does not have the Microsoft Exchange 2000 Server Post-Service Pack 3 Rollup software update installed.
• The recipient has configured Microsoft Outlook to send clear text signed messages.

Cumulative Rollup Information

To resolve this problem, click the following link to obtain the August 2004 Microsoft Exchange 2000 Server Post-Service Pack 3 (SP3) Rollup:

For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

Note Because of file dependencies, Microsoft Exchange Server 2000 Service Pack 3 is required for you to install this software update.

To work around this problem, follow these steps:

1. In Microsoft Outlook, click Options on the Tools menu, and then click the Security tab.
2. Click to clear the Send clear text signed messages when sending signed message check box, and then click OK.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

For additional information about digital certificates, click the following article number to view the article in the Microsoft Knowledge Base: