You may find yourself in a situation where an MMC snap-in errors out, and doesn’t allow you to reconfigure, fix, or use it. It becomes unusable.
In my case, this occurred on a system where I was trying to use the WSUS (Windows Server Update Services) snap-in, and it was configured for an old server that didn’t exist anymore.
When opening the WSUS MMC snap-in, it would report an error, give me the option to unload (which didn’t work), and do nothing else. There was no way to use or reconfigure it.
To resolve this, you need to clear your local configuration for the snap-in. Your user profile contains all MMC snap-in information and configuration in the following directory
When browsing, here’s what it looks like on my system:
In my case, deleting the “wsus” file, reset the MMC snap-in, and allowed me to use it again and configure it for a new server.
Let me know if this helped you!