Its your computer maintaining itself. Windows can detect when it is isn't being used, so it uses that time to defrag hard drives, sort out indexing to make file searches quicker etc. It may also download windows updates and apply any emergency patches etc. Windows does this to keep your computer running fast, and does it when your PC is idle so that it doesn't get in your way. IMO, I wouldn't worry about it. If its doing stuff that's fine, if you want to do stuff, Windows can wait until a better time. That is how its designed to work. This behaviour has existed in Windows for a long time, its not something new. I would not recommend trying to disable these features. If you do, you will need to manually do these things yourself in order to keep your PC running well. In response to what @fufsgfen said, I could be wrong but I would be very surprised if it was doing any form of telemetry beyond what is normally done. Telemetry is not a heavyweight task, it can be done in the background without the user noticing any perceivable difference. So I see no reason why Windows would wait until idle for that.