Can $WINDOWS.~BT Be Deleted?

Yes, the $WINDOWS.~BT folder can be safely deleted, as it is related to a previous or attempted Windows upgrade and is not required for normal operation once the upgrade process is complete.

However, it is recommended to remove it using the built‑in cleanup tools rather than deleting it manually:

For Windows 10 and Windows 11:

1. Open Settings.
2. Select System.
3. Select Storage.
4. Select Temporary files.
5. Select the checkbox for Previous version of Windows (this covers Windows.old and related upgrade folders such as $WINDOWS.~BT when applicable).
6. Select Remove files.

Alternatively, on supported versions you can use Storage Sense:

Windows 10:

1. Open Settings > System > Storage.
2. Under Storage sense, select Change how we free up space automatically.
3. In Free up space now, select Delete previous version of Windows.
4. Select Clean now.

Windows 11:

1. Open Settings > System > Storage.
2. Select Cleanup recommendations.
3. Select Previous Windows installation(s).
4. Select the Clean up button.

Note: Deleting previous Windows installation data (including content in $WINDOWS.~BT / Windows.old) removes the ability to roll back to the prior version of Windows.

References:

• Delete your previous version of Windows
• KB5012334—Delete the Windows.old folder using Storage sense in the Settings app