what is $windows.~ws
$Windows.~BT and $Windows.~WS are temporary folders and can be safely deleted. If you are unable to right-click on them and select Delete, you can use the following commands to change permissions and force-delete them. Right-click on Start button to open the WinX Menu. Select Command Prompt (Admin).
After you upgrade to Windows 10 you may notice two folders on your System or C Drive named $Windows.~BT and $Windows.~WS. These folders are created by Windows, during the upgrade process. The question now is â Is it safe to delete these $Windows.~BT and $Windows.~WS folders?