Originally Posted by
RobinOfLoxley:
“Use Media Creation Tool ("Create installation media for another PC" option) to download the ISO file instead of just selecting the Upgrade Now option
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Right-click .iso to Mount
or
Right-click .iso to burn to DVD.
or
Use Rufus to put .iso on USB Flash.
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You don't boot the DVD or Flash for first Upgrade. Run the setup.exe instead
Clean Install can be done at a future time/date by booting the media, after successful Activation has been confirmed, if desired.”
That was how I first attempted to upgrade, as I'd already made installation media on the first PC I successfully upgraded, and I thought it would save downloading it again (both PCs were on 8.1 Pro 64bit).
It gets a certain way then gives the error message "Something Happened. We were unable to determine if your PC would support Windows 10. Please run the setup again" or WTTE.
The only option is then to close. Tried it numerous times with the same result.
Then I installed the Media Creation Tool on that PC and tried the "Upgrade this PC" option. It downloads the Windows 10 files fine, but then when it tries to install it gives the same error message as before.
Annoyingly if I run it again it re-downloads all the files, even though they are already on the computer, so I only tried that twice.
The next thing I tried was to add a registry key "AllowOSUpgrade", which forces Windows Update to do the upgrade. That's when I got the error code 800703ED.
I also tried reserving through the 'Get Windows 10' popup, but that just tells me it's downloading in the background, which it isn't because it's relying on Windows Update to do it, and that has failed numerous times.
To answer
oilman, Windows was installed first and is on the first partition. The Linuxes were installed later.
However I notice in Disk management that the Windows partition is not the 'active' partition. The active partition is the Linux partition that is controlling grub.
It may be that if I make the Windows partition the active one, than that might solve the issue?