Did you just install the Anniversary update? If so, there’s more than 10 GB of data wasting space on your hard drive. On a laptop or tablet with a limited amount of storage, this can fill up your device quite a bit.
How to Delete The Windows.old Folder
If everything seems to be working fine after a few days, you can go ahead and remove these files. You don’t need to delete the Windows.old folder by hand, and you shouldn’t. Instead, you should use the Disk Cleanup tool, which will clean things up for you.
To launch it, open the Start menu, search for “Disk Cleanup”, and press Enter.
In the Disk Cleanup window, click the “Clean Up System Files” button.
Check the “Previous Windows installation(s)” option in the list. You can also check other types of files you want to remove from your hard drive to free up space here.
Click “OK” once you’ve selected what you want to remove. Disk Cleanup will remove the previous Windows installation files and free up the space on your hard drive.
If you do need to go back to a previous build of Windows 10 after removing these files, you’ll have to reinstall Windows 10 from installation media with an older build.