Have you noticed that there are “Windows.old” folder on your drive C? This is your previous files from upgrading (Windows 8.1/Windows 7) to Windows 10, this folder almost 20gb in sizes. You probably stumble on this site because you tried to delete this folder that it will keep saying “You need permission to perform this action” and unable to delete.
To remove this folder you have to use the Windows Clean Up Tool, follow my instruction below:
1. Go to “This PC” or previously “My Computer”
4. Then the “Disk Clean Up” will pop up, click the button on the bottom left “Clean up system files” to discover the previous windows installation.
Done! Now check your drive C and the “windows.old” folder are already deleted. Thanks for reading this article on the site!