must useful post ever.. did you do a fresh install after upgrading? I tried to pin multiple folders to quick access including my user folder and my drives with no errors.
have you tried a system restore to an earlier time ? Have you been messing with any reg edits or the like ?
I just did a system restore, didn't fix it. Guess I'll have to reinstall windows. And I wasn't messing with any reg edits before the problem started