The fastest way for deleting Windows.old folder

Since this is a special system folder, removing it via regular won’t work.

There are many approaches to this task, including disk cleanup tools and system settings. I found the fastest one to run either command line or terminal and executing:

takeown /F C:\Windows.old\* /R /A /D Y
icacls C:\Windows.old\*.* /T /grant administrators:F
Remove-Item -Path "C:\Windows.old" -Recurse -Force

Must be run as an administrator of course.