I don't know if anyone has posted this yet (the search is down), but here it is in any case. I run Windows 8.1 and when I tried to uninstall build 6xx via uninstall.exe, I got an error message saying something about a missing link. I tried removing it via configuration/remove programs and then I got an error message about not having the correct rights. I also tried running uninstall.exe as administrator but that didn't help either.
I found the solution somewhere on the web. If you set EnableLUA to 0 (false) in the regedit, then you're allowed to uninstall after rebooting. I did set it back to 1 (true) again because I like that extra security layer. I do find it odd though that I wasn't allowed to remove a program that I installed with that same user.