I am upgrading my Windows 7 setup (dual partition, one hdd), and I got this
Windows could not update registry data, cancelling install
And the setup is aborted, leaving an undeletable $UPGRADE.~OS and a windows.bt folder
What can be the problem?
This is sometimes the result of 3 things:
I would strongly advise you to do a clean install.
Have you ever messed with any registry key permissions? I recommend you back up your personal data, use the Upgrade Assistant to create USB/DVD (ISO) media, then boot from that and clean install Windows 8.