Is it safe to delete the 'windows.old' folder in the local disk after upgrading to Windows 10?

[Windows Central Question]

Windows.old folder, Windows 10 upgrade

 

[Dub-J]

You should be good to go, so long as you remove it through the disk cleanup utility (search disk cleanup on your computer). You'll need to click the "Remove System Files" button to see the option to remove previous Windows installations and temporary install files.

I removed both off my Surface Pro and it cleaned up about 15GB worth. Also be advised that you won't be able to roll back to Windows 8.1 after doing this.