I just noticed this last night after running several updates in groups of six on Windows Update, the folder, originally titled Windows.BT$ is now missing on my drive. I have hidden folders and files set to view and be seen. And its not showing up. Was it moved ? Or was it deleted outright ?
If it was moved, where was it moved to ? If it was deleted as per a update for it to be deleted, why did the HD space open up for that folder removal ?