I upgraded fine today to 1803, Windows 10 pro. Did a ton of work for about 2 hours, very stable.
Then I decided to put in the common AltTab fix, to get back the old fashioned AltTab. I have done this on every version of windows 10, not problems. (AltTabSettings Registry value)
After restart, windows would not boot. Black screen, blue spinning cursor. Waited 15 minutes, did a hard reset. No luck, same thing, windows wont boot. I did windows startup repair, which failed. I did windows system restore, which failed, as apparently 1803 turned OFF system restore?! I did a rollback to previous version of windows 1709, which thankfully worked, fast and no problems.
I created a system restore point manually, then ran the upgrade again, then booted into windows 1803 and confirmed that system restore is turned off by 1803 upgrade. I manually turned it on, created another restore point and restarted.
All is fine now.
It may be that the registry entry is no longer needed at all, or that it is incompatible with the new task Timeline feature.
TLDR: Dont use the previously suggested AltTabSettings Registry hack!! You will very likely encounter corrupted windows install. Also, make sure to check if your upgrade turned off system restore on the OS drive.
Edit: I did a restart after re-installing 1803, and same thing. Black screen, blue spinning cursor. Since I did not touch the registry, or any other settings, it has nothing to do with that. Back to 1709 we go! I have no idea if this is specific to my hardware and software, but at this point, I would be very cautious.
Edited by geekpryde, 01 May 2018 - 11:52 AM.