This is an offshoot of trying to fix UAC from re-enabling itself at logon after changing registry keys. I'm trying to remove all write permissions to the HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System key, but I keep getting an unknown account that adds itself back to the list after removing it, which I suspect is the culprit.
I read somewhere that this is because of inherited permissions, so I went to the root HKLM to remove it from there, but it still persists.
This unknown account does not appear in the list of user accounts under 'Users and groups' or anywhere else. I've upgraded my Windows installation from 8 to 10, but even then shouldn't it show up in the list of users?
Is there a way to stop this behavior and get rid of the unknown account?