Here’s a nice simple, yet frustrating one!   If you go through the Windows Anytime Upgrade site, make a purchase, get a key (so far so good) and then the key doesn’t work?!

You just get the error “Enter a different key”  and then  “The upgrade key you entered is for an edition of Windows that does not work with Windows Anytime Upgrade”



The fix?  Simple, reboot and the upgrade will continue automatically!