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:
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!