Exchange 2010 Decommission Error: "Please specify an existing server role to uninstall"

I've seen this problem on some message boards and even come across it myself when in a hurry and not paying attention.

You go to try to uninstall Exchange 2010 and you get an error saying:

"Some controls aren't valid - Please specify an existing server role(s) to uninstall"

The problem is: you have to Uncheck the Roles you want to uninstall. (If you read the line under Server Role Selection, it says to clear roles you want to remove).

I know that might seem backwards since by human nature you'd likely want to actually check things you'd want to uninstall, and MS should've written a separate uninstaller for Exchange, but...

Once you uncheck the role, hit Next and the installer will go to the Pre-req checks as normal.