In the process of using the Win10 system, the system files may be damaged due to some software or false operations. At this time, the system will report various errors, and even lead to the system can not start running properly. Then how to solve this problem? In fact, Microsoft has set a built-in file checker tool in the Win10 system, which can help users detect damaged files and restore them automatically, so how do you use it ? Here are the specific steps to repair damaged files using file checker under Win10 system.

What Is A File Checker Tool?
Before we learning how to use a built-in file checker, we must have a better understanding of what it is. System File Checker, referred to as SFC, is a utility tool of Microsoft Windows that allows users to scan all protected system files, check the integrity of system files, and then restore Windows damaged system files.
Related Commands And Functions
SFC commands are very useful for maintaining the entire system files. Let’s take a look at the related commands and functions of the System File Checker (SFC)
sfc /scannow
immediately scans the integrity of all protected system files and repairs as much as possible.
sfc /scanonce
scans the integrity of all protected system files at the next startup and repairs as much as possible.
sfc /scanboot
scans the integrity of all protected system files every time it starts, and repairs as much as possible.
sfc /purgecache
clears the file cache and scans all protected system files immediately. (Used to release disk space, you can use this command when your system is running low on disk space)
sfc / verifyonly
immediately scans the integrity of all protected system files without repair.
sfc /scanfile
scans the integrity of the reference file and fixes the file if a problem is found (the full path needs to be specified).
sfc /verifyfile
verifies the integrity of the file with the full path, but does not perform repair operations.
sfc / offbootdir
For offline repair, it specifies the location of the offline boot directory.
sfc / offwindir
For offline repair, it refers to the location of the offline Windows directory.
sfc / offlogfile
For offline repair, it selectively enables logging by specifying the log file path.
sfc / cancel
cancels scanning of all suspended protected system files.
sfc / enable
enables Windows file protection for normal operation.
sfc / quiet
replaces all incorrect system file versions without prompting the user.
sfc / cachesize = x
set the file cache size.
Note: we should use SFC command to repair Windows. If you do not use sfc /offwindir and sfc /offbootdir to specify the installation directory, you must be connected to the Internet for system repair.

How to Check And Repair System Files?
Through above, we know what is a file checker tool. At present, it is time for us to learn something about how to use it to check and repair system files.

Steps:
- Click both button CTRL and button F to open the Search bar of Windows system. And directly enter CMD in the search bar, opening it as an administrator.
- After opening, at the command prompt, enter sfc /scannow and then press Enter.
Tips:
- This sfc / scannow command will scan all protected system files, using the cached copy located in the compressed file %WinDir%\System32\dllcache to replace the damaged files.
- The %WinDir% placeholder represents the Windows operating system folder. For example, C: \ Windows.
Attention:
- Prior to verifying 100% complete, do not close the Command Prompt window.
- The scan results will be displayed after the end of this process.
Back to results:
- After the process ends, you may receive one of the following messages: Windows Resource Protection could not find any integrity conflicts. This means that you do not have any missing or damaged system files.Windows Resource Protection cannot perform the requested operation.
- If you want to resolve this issue, you should execute the System File Checker in safe mode, and make sure PendingDeletes and PendingRenames folder exist in the % WinDir% \ WinSxS \ Temp. Windows Resource Protection found the damaged files and successfully repaired them. Detailed information is contained in CBS.Log% WinDir% \ Logs \ CBS \ CBS.log in.
- If you want to view detailed information about system file scanning and restoration, you should go to How to view detailed information about the system file checker process. Windows Resource Protection found damaged files but could not repair them. Detailed information is contained in CBS.Log% WinDir% \ Logs \ CBS \ CBS.log in.
- If you want to manually repair the damaged file, you should check the detailed information of the system file checker process to find the damaged file, and then manually replace the damaged file with a known good copy of the file (in the same version of the system, the user can copy files in the CBS.log list to replace the same files in the failed computer).
- At the same time, if the user cannot repair it with the SFC file checking tool, he can also try to use the DISM command, which requires networking. Such as:
Run the following command as an administrator:
DISM.exe / Online / Cleanup-image / Scanhealth
DISM.exe / Online / Cleanup-image / Restorehealth
The first command is to scan all your system files and compare them with official system files. The second command is to restore those different system files to official system source files, which is similar to reinstalling.

The advantage of this method is that after repairing those system files, it will be restored to the official version of the source files. But it is only the system files can do this, other third-party software and user settings are completely preserved. Of course, this will take 15 to 20 minutes.
Conclusions
The above is about how to use the file checker to repair the entire contents of the damaged file under the Win10 system. Users in need can refer to the above method to operate.