Tried to turn off system last night (3/14), but Windows refused. " Task Host Window: “Closing 1 app and shutting down (To go back and save your work, click Cancel and finish what you need to). Task Host is stopping background tasks. (Microsoft\Windows\DeviceDirectoryClient\RegisterUserDevice) " Since it just sat there doing nothing for longer than I have patience for at midnight, I cancelled and googled for the issue. Results included such fixes as in place repair, sfc /scannow, DISM, clean install, etc. Many of these from MVPs on Microsoft forum. NOT What I finally figured out was that, being Patch Tuesday, Windows had begun to begin to begin updating. The 'background task' was something to do with BITS. Nothing indicated that it was doing so. No CPU, HDD, Network or Memory activity. It was in the peculiar situation I now label as "PATCH FUGUE" (def: a state or period of loss of awareness of one's identity, often coupled with flight from one's usual environment, associated with certain forms of hysteria and epilepsy ). I proceeded to close down - and left it 'blue screened' (not BSOD, just hung). In the night it settled itself - and when I rebooted, I found a failed update which had hidden in the rubble of the previous shutdown. Anyone have further insight?