Windows.old folder size in File Explorer

Did you just install the May 2019 Update? If so, there’s more than 10 GB of data wasting space on your hard drive—we had 24.6 GB! On a laptop or tablet with a limited amount of storage, this can fill up your device quite a bit.

If you have a computer with a large amount of available storage, you might not even notice this useless data. It’ll stick around for 10 days until Windows automatically cleans it up. But, if you’re pressed for space, you’ll want to clean it up as soon as possible.

These Files Let You Downgrade for 10 Days

Upgrading between “builds” of Windows 10–like from Windows 10’s October 2018 Update to Windows 10’s May 2019 Update–is treated the same as upgrading to an entirely new Windows operating system.

When you upgrade to a new “build,” Windows creates a Windows.old folder that contains the system files from your “old” Windows installation. This allows you to “go back” to the previous build of Windows 10 if you experience a problem with the new build.

RELATED: What Is the Windows.old Folder and How Do You Delete It?

However, this folder can use more than 10 GB of space on your hard drive. Windows will automatically remove it after 10 days, but you can remove it sooner to free up the space immediately.

Warning: You should only do this if your PC seems to be working properly. If you have some issue with the new version of Windows 10 on your hardware, you won’t be able to “go back” to the previous build without completely reinstalling Windows after you wipe these files.

You can go back to the last build of Windows 10 you had installed by navigating to Settings > Update & Security > Recovery and using the “Get Started” button under “Go back to the previous version of Windows 10.” This button is only present if the files are still available on your computer.

Go back to a previous version of Windows 10 recovery options

How to Delete the Windows.old Folder Using

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. In fact, some of the system files you need to remove are located outside of the Windows.old folder, anyway.

Starting with Windows 10’s April 2018 Update, you can now erase these files using the new “Free Up Space” tool in Settings. To access it, head to Settings > System > Storage > Configure Storage Sense or Run It Now.

RELATED: Use Windows 10's New "Free Up Space" Tool to Clean Up Your Hard Drive

Run Storage Sense now on Windows 10's May 2019 Update

Check the other settings here. By default, Storage Sense will also delete files more than 30 days old in your Recycle Bin when you run it.

Scroll down and check the “Delete previous versions of Windows” option here. If you don’t see this option in the list, either you’ve already deleted these files, or Windows 10 has already deleted them for you.

Delete previous versions of Windows in the Settings app

Click “Clean Now” to delete the previous versions of Windows and anything else you’ve chosen to remove with Storage Sense.

Bear in mind that the “Delete files in my Downloads folder if they have been there for over” option will remove files in your Downloads folder, which you may not want to do. Otherwise, it’s safe to delete all the types of data here if your PC is working properly, but bear in mind that the “Delete files in my recycle bin if they have been there for over” option will erase the files you have in your Recycle Bin.

Storage Sense's recycle bin and Downloads options

How to Delete the Windows.old Folder Using Disk Cleanup

You can also use the Disk Cleanup tool to clean things up for you. Disk Cleanup is now deprecated, but is still available in Windows 10.

To launch it, open the Start menu, search for “Disk Cleanup,” and press Enter.

Launching Disk Cleanup on Windows 10

In the Disk Cleanup window, click the “Clean Up System Files” button.

Clean up system files button in Disk Cleanup

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.

Previous Windows installation(s) option in Disk Cleanup

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.

Profile Photo for Chris Hoffman Chris Hoffman
Chris Hoffman is Editor-in-Chief of How-To Geek. He's written about technology for over a decade and was a PCWorld columnist for two years. Chris has written for The New York Times and Reader's Digest, been interviewed as a technology expert on TV stations like Miami's NBC 6, and had his work covered by news outlets like the BBC. Since 2011, Chris has written over 2,000 articles that have been read more than one billion times---and that's just here at How-To Geek.
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