How to use the DISM command tool to repair Windows 10

1. Open Start and type "CMD".
2. Right-click Command Prompt and click Run as administrator.
3. Type the following command to perform an advanced DISM scan and press Enter:
   •  DISM /Online /Cleanup-Image /ScanHealth
4. The advanced scan will scan the Windows 10 image and determine whether the Windows 10 image needs repairing. If it does, run the following command:
   • DISM /Online /Cleanup-Image /RestoreHealth

The steps outlined above will resolve issues with the system image, not with the installation of Windows 10 itself. Next, use the System File Checker (SFC) command tool to repair Windows 10 itself.