Important This article contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry


The Microsoft Message Queuing message files accumulate and are deleted only when you start the Message Queuing service.

Note Microsoft Message Queuing is also known as MSMQ.


The Message Queuing service deletes all empty message files for recoverable and transactional messages upon startup. Recoverable and transactional message storage files are paired and are of the form Lnnnnnnn.MQ and Pnnnnnnnn.MQ or Jnnnnnnn.MQ.For more information about Storage directory files, click the following article number to view the article in the Microsoft Knowledge Base:

174307 Interpreting file names in the Storage directory in Microsoft Message Queue Server and in Microsoft Message Queuing

If you do not restart the Message Queuing service, the disk storage usage remains at the peak requirement since the last restart of the Message Queuing service.


Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

The following fix installs a periodic cleanup of empty Message Queuing message files. The default interval for cleanup is six hours. This interval can be modified by a new registry key. To change the default interval, you must add
MessageCleanupInterval to the registry.

  1. Start Registry Editor (REGEDT32.EXE).

  2. Locate and select the following registry subkey:

    HKEY_LOCAL_MACHINE\ Software\Microsoft\MSMQ\Parameters
  3. From the Edit menu, click ADD VALUE.

  4. In the Value Name Field, type MessageCleanupInterval.

  5. In the Data Type Field, select REG_DWORD.

  6. For the data value, enter the desired interval in milliseconds (for example, 3600000 (decimal) for one hour).

  7. Exit Registry Editor to save the changes.

The next time you restart the Message Queuing service, the new interval will be used to cleanup empty message files.


Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.
This bug was corrected in Windows NT 4.0, Service Pack 4.


MSMQ Administrators Guide; topic: Message Delivery

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