Well, here I am trying to update from Windows 7 (Which I love by the way) and I am having these same problems,
I have now tried 11 times to install Windows 10 Pro, every time it crashes when it says it is going to reboot. It then goes back to Windows 7 with a message "Unknown error".
Looking at my Events Viewer, I get a different error each time, as follows...
error 0x80004005: Upgrade to Windows 10 Pro, version 1511, 10586.
error 0xc1900208: Upgrade to Windows 10 Pro, version 1511, 10586
error 0x80004005: Upgrade to Windows 10 Pro.
error 0xc1900208: Upgrade to Windows 10 Pro.
error 0x80004005: Upgrade to Windows 10 Pro
error 0xc1900208: Upgrade to Windows 10 Pro.
error 0x80004005: Upgrade to Windows 10 Pro.
error 0xc1900208: Upgrade to Windows 10 Pro.
error 0xc1900204: Upgrade to Windows 10 Pro
error 0xc1900204: Upgrade to Windows 10 Pro.
error 0x80240055: Upgrade to Windows 10 Pro.
There appear to be 4 error codes appearing, 0x80004005 , 0xc1900208, 0xc1900204 and 0x80240055.
So I am off to other threads to investigate these other errors.
I have done the full clean start before trying to install as well as a lot of other things.
I have just run Slim Cleaner so I will retry now, having done that and I will advise on my success , or lack of it.
I will look through the other error code threads first to see if I can find any other gems. If I find anything that works, I will let you know.
Good luck
William New Zealand