For me it works to tell MMC to use the v4 Framework, I've got v4.0.30319
set COMPLUS_version=v4.0.30319
start SomeConsole.msc
Check the workarounds: http://connect.microsoft.com/VisualStudio/feedback/details/474039/can-not-use-net-4-0-to-create-mmc-snapin
And this are my debug settings:
I use the 32 bit version of the console, and also had to add the into the "c\Windows\SysWOW64\mmc.exe.config" the following:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<startup useLegacyV2RuntimeActivationPolicy="true">
<supportedRuntime version='v4.0' />
</startup>
</configuration>
Hope it helps you. GL