Is there an actual known cause of this? I maintain 6 PCs at a local school, all of them have identical hardware and software. I attempted to upgrade all of them from RS2 to RS3 today with an RS3 image containing the latest CU and SSU. 4 of the 6 went off without a hitch and 2 of them stopped at 33% after the 2nd reboot. I don't actually need to fix these (will just pave over them) but I would love to know what actually causes this. Reports seem to indicate that at 33% drivers are being installed and some people have reported that removing a wireless card fixed the lockup but in my case all 6 systems are identical so hardware seems unlikely.
Most of the cases that I have seen are caused by an HDD that it's failing or are solved with a clean install instead of an upgrade. Is the bios version the same on all computers?
Everything is up to date and the computers are all identical. I know a clean install fixes this, not what I am asking. Searching around turns up this problem quite frequently but in most cases there is no resolution, at least nothing consistent. More or less I am just trying to see if anyone here knows more about this screamingly random glitch in an upgrade install. I left one of the 2 problem systems on 33%, will see if letting it sit long enough sorts this. Reading what others have said seems to imply that this wont work.
I think I remember this happening to me when I tried to upgrade using a multi-ISO with both home and pro on it. Try using the ISO that matches exactly and has only what you're trying to upgrade - x86 or x64 and home or pro.
Interesting, that has literally never been mentioned in the support threads but yes, the image I use for upgrades does indeed have both Home and Pro. Using DISM to extract just Home (what these systems all use) is a single enough task.
This happened enough to me in the past that I only use multi-ISO for clean installs and use specific ISO for updates.