It's worth noting that even though the System File Checker is designed to be a standalone tool, Microsoft recommends that you first run the Deployment Image Servicing and Management (DISM) tool if ...

The system file checker can, and should, also be run after clearing out a malware infection to potentially help repair some of the damage done – assuming nuke and repave is not the better option ...

3] Run the System File Checker program With the passage of time, system files get old and can become corrupted or even disappear from the system.