content: You can actually. You have to go through a bunch of shit and make a boot manager entry to do it though. I learned that looking up shit on trying to unlock the boot manager for my formally windows 8.1 install because it locked me out (refuses to boot the OS). I never did get it unlocked and from I can tell it isn't possible. You have to reformat the drive and reinstall the OS from scratch. The locked boot manager will not work at all even if you install windows 10 side by side (it allows this) and will not boot the upgrade/side by side. Reason: boot files become unwritable regardless of what permissions/repair disk you use. To back your data/settings up you must boot from another drive (safest) and browse the files that way (yes, that works. Seriously, they lock JUST the fucking boot files).