1 PC (mine) & 1 tablet (HP stream I got given) both issues from start to finish. PC was AMD drivers being stupid and WU having a later one than the site for some reason then a day later 15.7.1 comes out?? 5 people at work did it as well. 1 worked fine the rest non stop issues or didn't even start/work at all. 100% rush job on the RTM status IMO. Mainly driver issues but still, they really could have tested this upgrade process a bit better.
You can either do a reset AFTER you have upgraded and wipe all files/settings and bring it back to clean windows 10. The other way is to upgrade then extract your key and then perform a clean install via DVD/ISO and use the key you extracted.