MMC has detected an error in a snap-in and will unload it

Good morning AskPerf!  Madhurjya here from the Windows Performance Team to alert you on an emerging issue where random MMC snap-ins will fail after installing the June 2012 .NET updates.

After installing these .NET updates on a Windows 7 or Windows Server 2008 R2/SP1 machine, certain snap-ins will fail.  Most notably, the Server Manager and Event Viewer snap-ins.  The following errors will be displayed when you try and open these:

If you are receiving these errors, please install one of the following hotfixes for .NET Framework:

Hotfix Rollup 2688729 is available for the .NET Framework 2.0 SP2 on Windows 7 or on Windows Server 2008 R2

Hotfix Rollup 2688730 is available for the .NET Framework 2.0 SP2 on Windows 7 SP1 or on Windows Server 2008 R2 SP1

As a note, we have not seen this issue with 32-bit snap-ins.  To confirm this, you can launch 32-bit snap-ins with the following syntax:

mmc.exe /32 snap-in.msc

If the above hotfix does not resolve your issue, please open up a case with Microsoft Technical Support to further troubleshoot your issue.

Have a great weekend!

-Madhurjya