The sfc command is a tool for scanning and repairing system files that are corrupted or missing on Windows operating systems12. System files are essential files that are required for the proper functioning of the operating system, such as the GUI, drivers, services, and applications. If system files are damaged or deleted, the operating system may fail to start or run properly, causing errors, crashes, or blue screens.
The sfc command can be used to fix the issue of the PC that is unable to start the GUI, assuming that the problem is caused by corrupted or missing system files. The sfc command can be run from the command prompt, which can be accessed by booting the PC from the installation media, choosing the repair option, and selecting the command prompt option3. The sfc command can be used with different switches, such as /scannow, /verifyonly, /scanfile, or /offbootdir, depending on the situation and the desired action4. The most common switch is /scannow, which scans all the system files and repairs any problems that are found5. The syntax of the sfc command with the /scannow switch is:
sfc /scannow
The sfc command will then scan and repair the system files, and display the results on the screen. If the sfc command is able to fix the system files, the PC should be able to start the GUI normally after rebooting. If the sfc command is unable to fix the system files, the PC may need further troubleshooting or a clean installation of Windows.
Reference1: CompTIA A+ Certification Exam Core 2 Objectives, page 10 2: CompTIA A+ Core 2 (220-1102) Complete Video Course, Lesson 26 Documentation 3: How to use SFC Scannow to repair Windows system files 4: SFC Command (System File Checker) 5: How to Repair Windows 10 using Command Prompt