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

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Important This article contains information that shows you how to help lower security settings or how to turn off security features on a computer. You can make these changes to work around a specific problem. Before you make these changes, we recommend that you evaluate the risks that are associated with implementing this workaround in your particular environment. If you implement this workaround, take any appropriate additional steps to help protect your system.

Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 (http://support.microsoft.com/kb/256986/ ) Description of the Microsoft Windows Registry

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SYMPTOMS

Note This article discusses this problem only for the original release version of Microsoft Exchange Server 2003. To fix this problem in Exchange Server 2003 Service Pack 1 (SP1), you must obtain the hotfix that is provided in the following Microsoft Knowledge Base article:

843545 (http://support.microsoft.com/kb/843545/ ) Digitally signed messages remain in the Messages pending submission queue and are not delivered in Exchange Server 2003 Service Pack 1

When you send a digitally signed e-mail message on a computer that is running Microsoft Exchange Server 2003, 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.

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CAUSE

This problem may occur when the following conditions are true:

You run an antivirus program on the Exchange computer that uses the Antivirus Application Program Interface (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 server that is running the antivirus program.

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RESOLUTION

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:

http://support.microsoft.com/contactus/?ws=support (http://support.microsoft.com/contactus/?ws=support)

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

No prerequisites are required.

Restart requirement

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

Hotfix replacement information

This hotfix does not replace any other hotfixes.

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.

Date         Time   Version         Size       File name
--------------------------------------------------------------
10-Jun-2004  20:54  6.5.6980.93       367,104  Exsmtp.dll       
10-Jun-2004  01:37  6.5.6980.93        49,664  Mdbevent.dll     
10-Jun-2004  02:05  6.5.6980.93     3,208,704  Mdbmsg.dll       
10-Jun-2004  01:39  6.5.6980.93        24,064  Mdbrole.dll      
10-Jun-2004  20:55  6.5.6980.93        13,312  Mdbtask.dll      
10-Jun-2004  20:54  6.5.6980.93     5,046,784  Store.exe

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WORKAROUND

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.

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

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 server.

Alternatively, you can turn off transport scanning by setting the following Microsoft Windows registry entry to a value of 0:

HKLM\Software\Microsoft\Exchange\TransportAVAPI\Enabled

Note A value of 1 indicates that transport scanning is turned on.

To do this, follow these steps:

Click Start, click Run, type regedit, and then click OK.
Locate the following registry subkey:
HKLM\Software\Microsoft\Exchange\TransportAVAPI
Right-click Enabled, click Modify, type 0, and then click OK.
Quit Registry Editor.