Windows 10: Clean Up $WINDOWS.~BT

After updating my Windows 10 on my newly purchased Surface Pro 4 machine, I noticed that there are $Windows.~BT folder, which is 7.24GB  and Windows.old folder, which is 24.4GB on my hard disk

The $Windows.~BT come from Windows Update when updating to Windows 10 (Build 10586.36) and Windows.Old is the backup folder during Windows 10 upgrade.

Please refer to the following Steps on how to free up the disk space

  1. Run “Cleanmgr /sageset:100” on CMD * You can specify any number
  2. Check the following
    • Previous Windows Installation (s)
    • Template Windows Installation files
    • Temporary Setup Files


  1. It will modify the registry below


WIN10-DiskCleanup-02.jpgIn each of those keys is a Dword called ‘StateFlags***’ The last 4 digits correspond to the Sageset number used during the configuration.

  1. Warning will be prompt to alert you that “if you delete the previous Windows Installation or Temporary installation files, you will no longer able to restore the machines back to the previous version of Windows” and just click “yes” to continue
  2. Wait for the Disk Cleanup Task to finish, and I had regain back around 30GB of Disk Space.

Reference Link

  1. Automating Disk Cleanup Tool in Windows253597