I've made the fatal and stupid mistake of messing around with permissions. Specifically, I added a deny Write rule for administrators to my C: drive. In my efforts to revert this change I have attempted to change the owner of the drive from TrustedInstaller to myself and then removing the deny rule, however many folders remain unchanged and prompt an Access Denied window when changing the permissions. Obviously, soon after a restart most apps stopped working and could not open.

Next, I backed up whatever I could and tried resetting my PC. I chose the Keep My Files option when resetting my PC and let it do it's thing. Now the apps I re-install are able to work, but the folders that denied access earlier are still the same. I'm unable to do anything to these folders (C:\Users\...\Downloads, C:\Windows, C:\Program Files, etc.) other than see the contents.

I am willing to nuke it all and go back to factory settings if that is what it takes. How should I completely reset the permissions to default? Will a complete delete-everything PC reset change it back?

I'm using Windows 10. Unfortunately, I have no System Restore points set up.

  • An owner can always change permissions even if permissions say they can't. An administrator can take ownership of anything, even if permissions say they can't. These are known as privileges and are attached to users. Permissions are attached to objects.
    – Mark
    Feb 10, 2020 at 6:41
  • I am unable to claim ownership to files and folders in Program Files, with a prompt saying Access is Denied. Claiming as Administrators itself also gives the same prompt.
    – Octanis
    Feb 10, 2020 at 7:32
  • Use psexec. Start CMD from SYSTEM account in interactive mode and remove errorneous access permission.
    – Akina
    Feb 10, 2020 at 8:12
  • I've tried running it from SYSTEM (psexec -i -s cmd.exe) and then from the new terminal ran icacls C: /reset but it still says access denied
    – Octanis
    Feb 10, 2020 at 8:29
  • 1
    reset doesn't do what you think it does. Tell us what you did? In a normal windows installation reset will do almost nothing. Type icacls /?.
    – Mark
    Feb 10, 2020 at 8:37

1 Answer 1


After backing up my important files, I took the nuclear option of resetting the PC and allowing it to delete everything in the C: Drive.

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