Windows 10 Disk Usage 100% - Disable Microsoft Compatibility Telemetry

To find out why the Disk Usage is constantly at 100%:

1. Start the Task Manager: Right click on the toolbar and select Task Manager.
2. Click the Processes tab.
3. Click on the Disk column to sort the Disk Usage in descend order.
4. Right click on the header (Disk) and select Resource Values -> Disk -> Percents
5. Find out which process has the highest percentage of Disk Usage.

If Microsoft Compatibility Telemetry is always the No 1 process, we can disable it as below:

1. Right click the Windows Start icon and select Command Prompt (Admin) to open a command line window with the Administrator permission.
2. Run command taskschd.msc to start the Task Scheduler.
3. On the left panel, select Microsoft -> Windows -> Application Experience
4. On the middle top panel, find Microsoft Compatibility Appraiser.
5. Right click on Microsoft Compatibility Appraiser and select Disable.