Digitally signed messages remain in the Messages pending submission queue and are not delivered in Exchange Server 2003 SP1

When you send a digitally signed e-mail message on a computer that is running Microsoft Exchange Server 2003 Service Pack 1 (SP1), the e-mail message may not be delivered. When you view the Messages pending submission queue by using Exchange System Manager on the Exchange computer, the e-mail message may appear to be stuck in the queue.

Additionally, an event that is similar to the following event may be logged on your Exchange computer:

Event Type: Error
Event Source: MSExchangeTransport
Event Category: Exchange Store Driver
Event ID: 348
Description: A message could not be virus scanned - this operation will be retried later. Internet Message ID <6B909A01FBA732458FCEF70C0A141D2DD500@user-name.contoso.com>, Error Code 0x0.

Note This problem only occurs when the message is digitally signed. It does not occur if the message is digitally signed and encrypted.

This problem may occur when the following conditions are true:

• You run an antivirus program on the Exchange computer that uses the Antivirus API (AVAPI), such as McAfee GroupShield 6.0 for Microsoft Exchange.
• The AVAPI-based antivirus program is configured to use transport scanning.
• You send a digitally signed message as a user who is hosted on the Exchange computer that is running the antivirus program.

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

Exchange Server 2003 Service Pack 1

Restart requirement

You must restart the Microsoft Exchange Information Store service (Store.exe) on the Exchange computer.

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 file attributes) 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.

Warning This workaround may make your computer or your network more vulnerable to attack by malicious users or by malicious software such as viruses. We do not recommend this workaround but are providing this information so that you can implement this workaround at your own discretion. Use this workaround at your own risk.

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:

To work around this problem, turn off AVAPI transport scanning on the Exchange computer. To do this, see your AVAPI software documentation for more information.

Important If you turn off transport antivirus scanning, we recommend that you turn on information store-level antivirus scanning on your Exchange computer.

Alternatively, you can turn off transport scanning by setting the following Microsoft Windows registry entry to a value of 0:Note A value of 1 indicates that transport scanning is turned on.

To turn off transport scanning by setting the registry entry to a value of 0, follow these steps:

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Exchange\TransportAVAPI
3. Right-click Enabled in the right pane, click Modify, type 0, and then click OK.
4. Quit Registry Editor.

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

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