How to reclaim storage space after upgrading to Windows 11 26H2

• Windows 11 26H2 keeps the previous installation in the “Windows.old” folder after an in-place upgrade.
• The previous installation files can take up 20GB or more, depending on the previous configuration.
• You can remove the files through Settings > System > Storage > Temporary files > Cleanup system files.
• Deleting the previous installation prevents you from rolling back to the previous Windows version.

If you perform an in-place upgrade from an older version to Windows 11 26H2, the setup keeps a copy of the previous installation in case something goes wrong and you need to roll back to the earlier version. Windows stores this backup in the “Windows.old” folder on the system drive.

Although these files let you roll back to the previous version if needed, they can take up significant storage after the upgrade completes successfully. On devices with limited storage, the extra files can quickly become a problem.

If you have already upgraded to Windows 11 26H2 and need to free up space, Windows 11 includes options to remove the previous installation files safely. Depending on your previous installation and configuration, this can recover 20GB or more of storage.

In this guide, I’ll outline the steps to delete the previous installation files after upgrading to Windows 11 26H2 and reclaim some storage space.

How to free up space after upgrading to Windows 11 26H2

To reclaim storage space after installing a new version of Windows 11, follow these steps:

1. Open Settings on Windows 11.

2. Click on System.

3. Click the Storage page.

4. Click the Temporary files setting.

5. Click the “Cleanup system files” button.

   

6. Select the “Previous Windows Installation(s)” item from the list.

   

7. Clear the items you don’t want to clean up at this time.

8. Click the Remove files button.

Once you complete the steps, the security copy of the previous installation files will be deleted from your computer, freeing up several gigabytes of space.

One thing to note is that while deleting these files will prevent you from rolling back to a previous version of the operating system, the system will automatically purge the files after 10 days.

If, after deleting the previous installation files, the device still doesn’t have enough space, you will need to take other troubleshooting steps to free up space on Windows 11.

Finally, the system only creates a copy of the previous setup during an in-place upgrade, a process that reinstalls the operating system. For example, when upgrading from Windows 11 23H2 to 26H2 or from Windows 10 to version 26H2.

This won’t happen when upgrading from version 25H2 or 24H2 using Windows Update settings or by manually installing the Enablement Package.