IMAIL exception handling has been manually disabled

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at]  

Topic Last Modified: 2007-01-17

The Microsoft® Exchange Server Analyzer Tool examines the following registry entry to determine the setting for the ExceptionHandling registry value:


If the Exchange Server Analyzer finds the ExceptionHandling registry value configured with a value of 0, a warning is displayed.

In Exchange Server, IMAIL exception handling is turned on by default, and it cannot be turned off through the user interface. However, IMAIL exception handling can be turned off by using the registry.

Microsoft recommends that IMAIL exception handling remain enabled unless you are actively troubleshooting a problem. For example, you might turn off IMAIL exception handling if you have custom applications that trigger events based on bad Multipurpose Internet Mail Extensions (MIME) or MAPI content. Microsoft recommends that IMAIL exception handling be turned off only on the advice and direction of Microsoft Product Support Services support professionals.

This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore the registry if a problem occurs. For information about how to restore the registry, view the "Restore the Registry" Help topic in Regedit.exe or Regedt32.exe.

  1. Open a registry editor, such as Regedit.exe or Regedt32.exe.

  2. Navigate to: HKLM\System\CurrentControlSet\Services\MSExchangeIS\ParametersSystem\InternetContent.

  3. Double-click ExceptionHandling:

  4. To turn off IMAIL exception handling, type 0 in the Value data field.

  5. To turn on IMAIL exception handling, type 1 in the Value data field.

  6. Close the registry editor and restart the Microsoft Exchange System Attendant service for the change to take effect.

Before you edit the registry, and for information about how to edit the registry, see the Microsoft Knowledge Base article 256986, "Description of the Microsoft Windows registry" (

For more information about the ExceptionHandling registry value, see the Knowledge Base article 832174, "There is no option to turn off IMAIL exception handling in Exchange 2000 Server" (


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