Microsoft Compatibility Telemetry is a Windows 10 service sending technical data to Microsoft periodically. It is one of the "disk killers" in Windows 10 (services that contribute to sending your disk usage to 100%). You can find and disable it in Task Scheduler, under:
Microsoft\Windows\Application Experience
You may be surprised also to find multiple triggers which activate telemetry collation and delivery to Microsoft on a regular basis. To turn it off, end the task and disable it from the Actions window.
