Yeah, that will be mayhem for all users with problems switching from business to private accounts.

I don't know how many times I had support cases were the old accounts kept popping up, despite following any MS support documents. In the end I often desperately search the registry for anything matching disjunct parts of the old account and delete it inside of regedit. MS is so incompetent in keeping their stuff in order, it's amazing anything is working at all.