I have tried all the "fixes" that Martin and everyone else has tried on this forum and a couple of other forums but the same problem exists.
I have three office machines and a personal laptop and have tried numerous times with all these machines to no avail. So it is not simply a "driver" or "external component" issue which with the laptop doesn't apply anyway.
The one thing I have noticed that from the Store download page the instructions state that a Microsoft licence acceptance pop up should appear after the download and if it is NOT accepted the machine will restore the previous version of windows. That pop up has never appeared after any of my downloads, the installation begins immediately without acceptance.
Could this be the reason for failure I wonder?
Is this page for accepting the license agreement missing from some download server files?
It is also not 8.1 RT I am trying to update but 8.1 Pro.
Somebody somewhere has cocked up the download files with some parts missing or corrupt I would suggest.
Could it be that the mighty and all powerful Microsoft corporation has fallen on it's collective face at the last hurdle, perish the thought.
PS I am using the UK download servers.