Management Group Fails to Start after OpsMgr 2007 R2 upgrade - Logs event IDs 20056, 2000

After you upgrade to System Center Operations Manager 2007 R2 you may notice that a management group fails to start and you see the following events being logged:

Event Type: Error
Event Source: OpsMgr Connector
Event Category: None
Event ID: 20056
Description: Failed to initialize the IPC channels for other processes to communicate. The HealthService might fail to start.

Event Type: Error
Event Source: HealthService
Event Category: Health Service
Event ID: 2000
Description: The Management Group MGName failed to start. The error message is Unspecified error(0x80004005). A previous message with more detail may have been logged.

This can occur if files that OpsMgr relies upon get added to the Global Assembly Cache prior to the upgrade.  These files are not added as part of a Microsoft setup routine, rather these get added by either 3rd party software or by a user adding them directly to enable some sort of utility to run.  Because of this they are not upgraded by the regular setup routine.  Because OpsMgr will use files in Global Assembly Cache first, these old, non-upgraded files can cause the symptoms described above.

To resolve this issue use either of the following methods:

1. Use Gacutil /u with the dllname that was added then restart the computer. Gacutil is available from https://msdn.microsoft.com/en-us/library/ex0ss12c(VS.80).aspx

or

2. Navigate to C:\windows\assembly and look for the dll affected, right click on this DLL, and select Uninstall.

Once you do either of these, the management group should start and the events should no longer be logged.

More Info:  The global assembly cache is located at c:\windows\Assembly see https://msdn.microsoft.com/en-us/library/yf1d93sz(vs.71).aspx for details.

J.C. Hornbeck | Manageability Knowledge Engineer