Since it was first released there has been widespread concern about Windows 10's data collection, as the operating system collects various kinds of data and sends it back to Microsoft. The company says it uses this information to determine how well systems are running and get a heads up on problems that users are facing. Telemetry isn't new to Windows, but prior to Windows 10 it was always opt-in, through schemes such as the Customer Experience Improvement Program and Windows Error Reporting. If you didn't want to send anything, you could turn it all off.