How to restore the local drive "C:\" to its default permissions?

Question

I changed my permissions on local drive C:\ and now many applications/system things not working properly. I was wondering how can I restore the local drive C:\ to its default permissions? And the sub folders and files?

Answer 1

The only way to correctly and completely resolve this issue is to do a clean reinstall of the OS. Even a Repair Install will leave application issues.

The primary issue here is that permissions will shift and change based on how you use your computer, in big and small ways. There is no real method of documenting every possible correct permission setting that you could then refer to in order to recreate the correct permissions, and even if there were, it would be an astoundingly complex task to set those permissions on each individual object in your computer's file system.

For this reason, both practically and realistically speaking, the correct course of action is to backup any personal data you need to save, complete a clean install of the OS over this broken partition, and don't change permissions in the root of the drive next time.

Answer 2

To reset permissions for the folder: icacls C:\ /reset

To reset permissions for the folder, its files, and subfolders: icacls C:\ /reset /t /c /l

Source

Answer 3

Move to root C:* and type icacls C:*. /t /l /c /reset .. wait for the process to end.