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Windows.old folder

System folderWindows 10, 11Safe to delete: Yes
Checked against official documentationLast reviewed 1 min read

Windows.old is a folder that Windows Setup creates on the system drive when you upgrade or reinstall Windows over an existing installation. It holds the previous Windows installation so you can go back to it or recover files, and Windows deletes it automatically after a limited period, usually ten days.

1What it contains

The folder keeps the previous system files, installed programs and the user profiles of the old installation, for example C:\Windows.old\Users\<name>\Documents. It is often 10-30 GB because it is a full copy of the earlier Windows.

While the folder exists, Settings > System > Recovery offers a 'Go back' option for a limited time after a feature update.

2When it is safe to remove

Removing it is safe once the new Windows works, your devices have drivers and you have copied any personal files you still need from the old user folders. After removal you can no longer go back to the previous version.

Windows removes the folder by itself after the rollback period, so deleting it early is only about getting the space back sooner.

3Why it cannot simply be deleted in Explorer

The files belong to system accounts and are protected, so Explorer usually refuses or deletes only part of them. The supported ways are Storage Sense ('Temporary files' > 'Previous Windows installation(s)') and Disk Cleanup with 'Clean up system files'.

How to remove Windows.old

  1. Open C:\Windows.old\Users and copy any personal files you still need.
  2. Open Settings > System > Storage > Temporary files.
  3. Tick 'Previous Windows installation(s)' and select 'Remove files'.
  4. Alternative: run cleanmgr, choose drive C:, select 'Clean up system files' and tick 'Previous Windows installation(s)'.

Cautions

  • After removal the 'Go back' option in Recovery disappears.
  • Do not take ownership of the folder and delete it by force: files you still need may be inside and the supported tools are safer.

Sources

  1. Free up drive space in Windows (Microsoft Support) support.microsoft.com
  2. Recovery options in Windows (Microsoft Support) support.microsoft.com
  3. cleanmgr (Microsoft Learn) learn.microsoft.com

Note: Rain Cleaner lists Windows.old with its size and what you lose before anything is removed.

Last reviewed: