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Microsoft KB Archive/169686

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Knowledge Base

Article ID: 169686

Article Last Modified on 10/28/2006


  • Microsoft Exchange Server 4.0 Standard Edition
  • Microsoft Exchange Server 5.0 Standard Edition

This article was previously published under Q169686

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information on how to do this, view the "Restoring the Registry" online Help topic in Regedit.exe or the "Restoring a Registry Key" online Help topic in Regedt32.exe.


The Internet Mail Service (or Internet Mail Connector, in version 4.0) may shut down and the following events may appear in the Event Viewer Application Log:

   An error was returned from the messaging software the Internet Mail
   Service uses to process messages on the Microsoft Exchange Server.  It
   is possible that the piece of mail being processed at the time will not
   be delivered. The message that was being processed has been moved to the
   "BAD" folder.  Use the appropriate utilities found in the SUPPORT
   directory of your Exchange CD to view and manipulate these messages.

   The error 0x80040115 was encountered while trying to communicate with
   the message store. An attempt to refresh the connection will be made.
   If not successful, the service will be shut down.

   An error was returned from the messaging software the Internet Mail
   Service uses to process messages on the Microsoft Exchange Server. As a
   result, the message in spool file 3XDW6BQJ failed to be delivered. The
   message has been moved to the Imcdata\In\Archive directory.

   The error 0x8004011d occurred while trying to refresh network
   connections to the Information Store. The Internet Mail Service is being
   shut down.

   A serious error has occurred while trying to send mail into the Exchange
   Information Store. The Internet Mail Service is being shut down.

This series of events repeats itself when you restart the Internet Mail Service (IMS) or Internet Mail Connector (IMC).


The number of threads available to the IMC or IMS from the Information Store (IS) may be too low. Check the following registry setting:

   \ParametersSystem\Max Threads(Private+Public).

The Max Threads(Private+Public) value defaults to 0x20 when Microsoft Exchange Server is installed. However, if you run Performance Optimizer and leave the default values, select all Server Type options, or choose a low number of users, this registry parameter is decreased to 0x5. This in turn prevents the IMC or IMS from connecting to the IS to deliver new mail or retrieve outbound mail.

This registry setting is not visible unless Performance Optimizer has been run or you add it manually.


WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall Windows. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" online Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" online Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.

To work around this problem:

  • Change the registry setting so that you increase the number of threads available. For instance, changing it to 0x14 will provide a maximum of 20 threads.


Performance Optimizer records all the changes it makes in a log file in the Windows NT \system32 directory, called perfopt.log. Every time you run the Optimizer, this log file is appended with the latest changes. You can review this log file for changes to the Max Threads(Private+Public) registry setting.

Additional query words: exfaq

Keywords: kbusage KB169686