This post will be short and sweet. For a while now I have been getting random failures when I try to open things like AD users and groups, DNS, DHCP, etc. Somedays it will work fine and some days it just fails with this message.
Here's the fix:
Navigate to C:\Windows\Microsoft.NET\Framework64\v2.0.50727\config
Find the file called "machine.config" and rename it to "machine.config.old"
Now copy the "machine.confog.default" file and paste it in the same folder again.
Find the file named "machine.config - Copy.default" and rename it to "machine.config"
Now you should be able to open your Microsoft management programs that run in the MMC.