Event ID 4100 appears repeatedly in Event Viewer on Windows 2000 Professional or on Windows Server 2003


On a Microsoft Windows 2000 Professional-based or Windows Server 2003-based computer, the following information about event ID 4100 may appear one to two times a day in Event Viewer:

Event Type:Warning
Event Source:EventSystem
Event Category:Firing Agent
Event ID:4100
Computer:computer name
Description: The COM+ Event System failed to create an instance of the subscriber {6295DF2D-35EE-11D1-8707-00C04FD93327}. CoCreateInstanceEx returned HRESULT 8000401A.


To resolve this behavior, use the Regsvr32 tool to unregister the Mobsync.dll file from the server:

  1. Click Start, click Programs, click Accessories, and then click Command Prompt.
  2. Type the following line, and then press ENTER:
    regsvr32 "%systemroot%\system32\mobsync.dll" /u
  3. Quit Command Prompt.
After you unregister Mobsync.dll, Client Side Caching (CSC) no longer works. The behavior described in the "Symptoms" section of this article does not affect CSC functionality, but unregistering Mobsync.dll does.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information

If you upgrade a workstation that is experiencing this problem to Microsoft Windows XP, you see event ID 4356 on that workstation.

For more information about using Regsvr32, click the following article number to view the article in the Microsoft Knowledge Base:

249873 Explanation of Regsvr32 usage and error messages