Mail clients cannot access some PGP-encrypted messages after you upgrade from Exchange 2000 Server to Exchange Server 2003

After you upgrade a computer that is running Microsoft Exchange 2000 Server to Microsoft Exchange Server 2003, e-mail messages that were sent before the upgrade and that are encrypted with Pretty Good Privacy (PGP) encryption are no longer accessible.

When you try to open a PGP-encrypted message in Microsoft Outlook, you may receive the following error message:
When you try to open a PGP-encrypted message in Microsoft Outlook Web Access (OWA), you may receive the following error message:
When you try to open a PGP-encrypted message in the Mdbvu32.exe utility, you may receive the following error message:
If you move the mailbox that contains the PGP-encrypted e-mail back to an Exchange 2000 computer, you can access the message and you receive no error message.

This problem occurs because the Exchange 2003 Virus Scanning API returns a MAPI_E_NO_SUPPORT error and blocks access to a message that is encrypted with PGP encryption.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

Because of file dependencies, this update requires Exchange 2003.

Restart requirement

You do not have to restart your computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other software updates.

File information

The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

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

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