When you choose the upgrade path to move to a more recent version of Windows, whether from XP to 7, from 8 to 10, or anything else, you will usually find a large folder on your C drive that takes up tens of gigabytes, and that doesn’t seem to do anything. It’s called Windows.old, and you won’t see it on clean installations of Windows. The folder can’t be deleted with a simple click of the Delete button, either. You usually get an error message to that effect. What is Windows.old, then, and what is it doing on your drive?
Don’t worry, it’ll go away
As the name suggests, Windows.old is a full record of your old operating system; it includes a copy of the OS itself, as well as every one of your old programs and files. Windows saves all of it just in case. Not only can you simply open the folder to look for files, you can count on it if you just want things to go back to the way they always were, and return to your old operating system.
Windows doesn’t keep Windows.old forever, though. It gives you 30 days to make up your mind. If you aren’t rolling back your OS upgrade, it assumes that you’re happy with it, and deletes Windows.old.
Going back to your old Windows
If you upgraded to your current version of Windows (instead of choosing a clean install), you have up to a month to downgrade or roll back. For instance, if you upgraded to Windows 10 from Windows 7 or 8.1, all you need to do to go back is to open the Settings app in 10, click on Update and Security, and select Recovery.
Once recovery is set in motion, you see a Get started button under the Go back section; when you click it, Windows 10 uses the information that it finds in the Windows.old folder to bring back the old operating system. The process is only as simple if you have Windows 10, though. It’s a complex process if you have Windows 7.
What if you want to get rid of Windows.old right now?
While Windows does get rid of Windows.old after waiting a month to see if it’s needed, you could have trouble setting aside tens of gigabytes for it until then. If you need to space right now, you’ll need to look into deleting it. As long as you sure that you want to keep your current operating system, it’s easy enough to do.
Windows doesn’t allow for manual deletion of the Windows.old folder. It’s easy with Windows’ own Disk Cleanup tool. Use Search Windows for it, and run it when you find it. You’ll find an item called Previous Windows installations on the list of Files to delete. All you need to do is to check the box next to it, and set the cleanup in motion.