Windows 10: Issues after taking ownership of C:\

Hi there. I've been rather stupid and transferred ownership of C:\, including system32, to my account (the administrator and only user). While I would instantly switch it back, due to an unrelated reason I restarted my computer (Surface Pro 4). Since then I've done research and found that it was definitely not a good idea to transfer ownership to begin with.

When I turn the computer on, it boots up normally until the point where it (presumably) leads to the login screen, but remains with the spinning-dots loading symbol. After some experimentation it still responds to the keyboard shortcut to change brightness. Also, upon CTRL+ALT+DELETE it goes to the normal screen except without any text. The buttons for wifi, ease of access, and sleep/shutdown/restart on the bottom-right are present and do work. When I hold down the power button the normal 'slide to shutdown' screen appears and is functional.

Is there any solution? Since I can't log in or access File Explorer (or Command Prompt) I can't reset permissions.

Many thanks for any help at all.

:)

 

I don't know if it can do what you need, but you can get access to the command prompt from installation media Command Prompt at Boot - Open in Windows 10 - Windows 10 Forums

 

Thanks for the response. After doing some more digging I've found a way to access that, and am currently looking through other places to find the right command (I'm only familiar with Unix).

 

Just a thought, but what about creating a Bootable PE Rescue Disk?

To be honest, I just discovered this myself, but it looked like it might offer some help.

 

If this is what I think it is, then it's sadly not really possible. When I tried to make a bootable USB (since I don't have any essential personal files), it became apparent that you need another Windows machine to set it up. This is another problem, because I am surrounded by Macs. I don't have access to any other Windows computers very easily at all.

In response to my previous post, I've been trying to change permissions for System32, C:\Windows, and now the entirety of C:\ to TrustedInstaller (the default) through command line. Although it says that it's successful, each time I subsequently restart it doesn't work. I'll try a few more variations thereof, regardless.

Thanks once again.

 

What command did you use to take ownership?

 

Code: icacls C:\ /setowner "NT SERVICE\TrustedInstaller" /T /C[/quote] I used Code: takeown /F C:\Windows /A[/quote] beforehand when trying to do it just for the Windows folder, as suggested by another forum.

EDIT:
My attempt to use the first command has finished and hasn't worked.

 

I should have a good answer for you in a little while, but I'm not sure you can undo it.

 

I see. Thank you regardless, especially for your speedy response. If it's impossible then I'll just reset the machine and make sure I learn from this mistake.

 

Your best chance would probably be to try a system restore to a point before you took ownership. Hopefully you have restore points to that time. System Restore Windows 10

 

Have you tried booting into safe mode? If you can get it to boot, if the system restore doesn't work, try a Repair Install Repair Install Windows 10 with an In-place Upgrade

 

Interestingly, when I previously followed these steps (from the sign-in screen) the screen that is supposed to show in step 3 never occurred, and it just went back to the loading symbol as before. And as I said in a previous post, I cannot do the boot from an USB due to lack of (functioning) Windows machines. So I guess that approach doesn't work either.

I've gone and reset (refreshed?) Windows whilst keeping my files to see if that works. I'll give an update on the results.

 

If you need it, you may be able to download the installation media on a Mac. If you use the Media creation tool and select the option to create a USB drive. The tool should create it directly to the USB, I assume. I have no experience with a Mac, but the tool may work.

 

Just had another look at Microsoft's help page for that. It seems that either I misread or misunderstood completely, because apparently it will work on a Mac as long as I then put it onto a general USB drive. I'll try that next, then, after this reset's finished (currently 37% through the installation).

Both the installation media and the full reset lose all my personal files (since I haven't made a recovery point; I'm not very smart), so I suppose there's no real reason to favour one over the other. Many thanks for the help.

 

Just finished the re-installation (whilst keeping personal files). My personal files are still here, so that's good. It'll be a tiny bit of a hassle to get all the apps again, but it's not essential, and I use Firefox so the only thing I really lost otherwise is the local internet cache (passwords and details are saved elsewhere). If anything it's been a valuable learning experience (I love clichés).

Many thanks to essenbe. I'll mark this as solved for now.