I've tried every solution I could research to get an in place upgrade of WIN10 (1709):
Media Creation Tool
Upgrade Assistant
1809 ISO
20H2 ISO
21H1 ISO
Disable UAC
Disabled all relevant local security policies that may interfere
Disabled AV agent
SFC / Scannow
SetupDiag.exe
But each and every time it fails around the 80-85% mark with the following error
Failed to mount WIM file C:\$WINDOWS.~BT\Sources\SafeOS\winre.wim. Error 0x80070522
I'm a local admin as well as running the setup.exe as admin, but for some reason the DISM command cannot mount the winre.wim file at a crucial stage in the upgrade process, so it simply fails each time.
Can anyone think of something I've missed that would cause the permission error each time?