All programs listed for removal have been uninstalled.
System has been booted.
No devices plugged in except keyboard, mouse and the internal DVD-RW.
FRST ran again, see attached.
1. Temporarily uninstall your LAN driver and unplug the cable from the machine.
2. Create a new local admin user account and call it Test.
3. Sign into Windows with that account.
4. Attempt the upgrade from the iso.
Note: If you don't have the iso, please download it prior to uninstalling and unplugging your network.
I can't do that just yet, because I'm working on this PC remotely and I wont be back there for over a week.
The files and folders from the latest Win10 ISO have been extracted into a folder called "C:\Win10_1909", which is where I have been running the upgrade from up until now.
I will go ahead and I try the upgrade one more time. If it fails again I'll have to leave it until I can go out there and work on it with the NIC disabled/uninstalled.
Thanks a lot for all your help.
Sadly still failed, but with a different error this time:
0xC1900101 - 0x20017
The installation failed in the SAFE_OS phase with an error during BOOT operation