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XWEB: MMP files Created by MAPI and CDO

This article was previously published under Q166599
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 Description of the Microsoft Windows Registry
When you use Collaboration Data Objects (CDO) or Messaging Application Programming Interface (MAPI) in an ASP page to access information on Microsoft Exchange Server 5.5 or Microsoft Exchange 2000 Server, files with an .mmp extension are created in your %windir% directory by default.
The .mmp file is a temporary file used by Extended MAPI (and hence CDO) to store certain profile information during the active session. This file should be deleted after the user logs off and the session is closed.

Because these files are created dynamically, the account running the ASP page (usually the Microsoft Internet Information Server (IIS) Anonymous Logon account: IUSR_Server) needs to have change permissions on the %windir% directory.

Also, a registry key exists that you may use to control which directory creates the .mmp files.


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.
If the following registry key is present, the .mmp files will be created there instead of the \Winnt directory:
HKEY_LOCAL_MACHINE/Software/Microsoft/Windows Messaging Subsystem
To create the registry entry, do the following:
  1. Start Registry Editor (Regedt32.exe) and go to the following key:
    HKEY_LOCAL_MACHINE/Software/Microsoft/Windows Messaging Subsystem
  2. On the Edit menu, click Add Value.
  3. Type the following values:
String Value: ProfileDirectory Value Data: Path to the directory you want the temporary files to be created in.Example: C:\MyComputer\Temporary.				
If the registry key/value is not present, the .mmp files are created in the Winnt directory as before.

  • The IIS Anonymous Logon account (IUSR_Server by default) must have change permissions for the directory that you specified as the value for ProfileDirectory.
  • MAPI will only check this registry key once per process, so if a process using MAPI is already running when the registry key is set, the process may continue to use the old location to store MMP file. In order to force MAPI to read the registry key, stop and restart the process which uses MAPI.

    For example, if IIS is running an asp page under DLLHost.exe, then DLLHost.exe must be restarted to use this registry key.

Article ID: 166599 - Last Review: 02/26/2007 21:25:44 - Revision: 5.4

  • Microsoft Exchange 2000 Enterprise Server
  • Microsoft Exchange 2000 Server Standard Edition
  • Microsoft Exchange Server 5.0 Standard Edition
  • Microsoft Internet Information Server 3.0
  • kbbug kbusage KB166599