By Ivy / Last update July 1, 2021

What is a system file?

A system file is a more than important part of the system, as its name. It usually comes as part of the operating system which is used for its core operations. And it’s located in a system folder, such as, System32, which cannot be deleted even through the use of permissions. The aim is to protect system files from deletion mistakenly.

The system files in Windows can make your computer run normally. If it’s corrupted or missing, your computer will not work properly.

How to repair Windows if system files are corrupted or missing?

Behind corrupted or missing system files, there are many reasons, such as sudden power drops, third-party programs, virus attacks, human error. Once you receive the error message that implies the system files is damaged, you can repair system files using cmd. The system file checker is the best way to start the troubleshooting.

#1: System files integrity check and repair in Windows 7/8/10

For system file repair in Windows 7/8/10, you can try SFC (system file checker) command first. It can scan your computer and find the corrupted files, then restore the corrupted system files.

Step 1. Type cmd in the search box and then select Run as administrator.

Step 2. Type sfc /scannow in the command prompt and hit Enter.

SFC Scannow

If your computer is unbootable, you still can repair system files using CD/DVD that come with your computer. You can boot from it, then directly press Shift +F10 to open command prompt and type the above command. 

#2: View SFC log and repair system files manually

After the sfc /scannow end, you may get there are still some unrepaired system files with error message like “Windows Resource Protection found corrupt files but was unable to fix some of them. Details are included in the CBS.Log %WinDir%\Logs\CBS\CBS.log. ”

In this case, you should create a SFC log file with the CBS log file, then find the corrupt or missing Windows file and replace it with a good one.

Create and View the SFC log file

Step 1. Open cmd as administrator, enter the following command in the pop-up window and then hit Enter. This operation can help you create a sfclogs.txt file on the desktop.

findstr /c:”[SR]” %windir%\Logs\CBS\CBS.log >”%userprofile%\Desktop\sfclogs.txt”

Step 2. Open the sfclogs.txt file, find the date and time entry for a file that could not be repaired.

Note : the Sfcdetails.txt files use Date/Time SFC details format, thus you need to verify the date and time entries. Then, you can use it to find the unrepaired files.


Repair damaged system files in Windows 7/8/10

1. Find known good system files copies on another computer with the same version of the operating system.

2. Open CMD as administrator.

3. Type the following command to take ownership of the corrupted files and hit Enter to run it.

takeown /f C:\Windows\System32\appraiser.dll

Note: C:\Windows\System32\appraiser.dll refers to the path and name of the corrupted system file. You should replace it.

4. Type the command below to give a full admin access to the corrupted files and then hit Enter.

icaclsC:\Windows\System32\appraiser.dll /Grant Administrators:F

5. Type the following command to replace the damaged system files and press Enter.

copy D:\Files\appraiser.dll C:\Windows\System32\appraiser.dll.

Note: D:\Files\appraiser.dll refers to the path and name of the known good file. You should replace it.

6. Type yes in the window and then Press Enter.

7. Type sfc /verifyonly command to check the integrity of all the system files and press Enter to move on. Wait until the process is 100% complete.

Besides, you can use DISM command utility in Windows 8/10. It will automatically fix SFC Scannow not working as well as scan and repair system files in Windows 8/10.

To run DISM command line, you need to open the command prompt as administrator and type the following command in the pop-up window and hit Enter.

DISM /Online /Cleanup-Image /RestoreHealth

#3: Repair Windows 7/8/10 system files without CD

For the majority of users, the command line is a complicated thing. And it’s much easier to make a mistake. Thus, I recommend you a Windows built-in tool named System Restore. It’s easy to learn and operate.

Step 1. Type system restore in the search box and select it.

Step 2. Select one of the options as shown in the following and follow the wizard until the last step. For system restore point, you have two options, including Recommended restore, Choose a different restore point. If the recommended restore point is available, you’d better tick it. If not, you can tick Choose a different restore point and find the available restore point.

System Restore

Sometimes, you will find that there is no system restore points in Windows 7/8/10. Don’t worry about it. You can try the last two solutions to repair system files.

#4: Repair Windows 7/8/10 system files without losing data

To make sure the security of your data, backup system is the best way. It will keep all your programs and files intact. And it’s very easy to operate, even for a beginner.

A proper backup and restore software is very important for you if you want to backup system in simple ways. I recommend you free AOMEI Backupper Standard.

To backup system, you can download free AOMEI Backupper Standard, install and launch it. Click Backup and System Backup to start the operation and then follow the wizard until the last step. One more things, you can backup to external hard drive, USB drive, cloud drive like Dropbox, Google Drive, etc.

System Backup

To restore your backup, you can open AOMEI Backupper, click Restore and select a system image first and then follow the wizard to finish the rest of steps.

Select Task

If your image is saved on the external hard drive, you need to create a bootable disk first. And then, use the bootable media to boot your computer and connect the drive containing your backup image. At last, restore image from external hard drive based on above wizard.

What’s more, you can do system clone to HDD/SSD in advance. It’s simpler. You just need to replace the old drive with the cloned drive and boot from it. However, system clone is only available on the paid version, such as AOMEI Backupper Professional, AOMEI Backupper Server, etc. You need to upgrade the free version to a paid version based on the operating system you are using.

#5: Repair system files with onekey recovery software

To create a system image backup from which you can repair corrupted system files, you can also try AOMEI OneKey Recovery. It enables you to save system image on a custom recovery partition and recover corrupted computer using the "F11" or "A" key during computer startup. All operations are quite simple.

To backup system files, just choose OneKey System Backup after launching AOMEI OneKey Recovery.

OneKey System Backup

To perform system recovery when your computer boots normally, open the program and choose OneKey System Recovery. If your computer fails to boot, press F11 or A during startup (Legacy boot) or choose AOMEI OneKey Recovery in boot menu (UEFI boot) to launch the program and perform system restore from Windows PE.

OneKey System Recovery

Wrapping things up

Reading here, you may already know how to repair missing system files in Windows 7/8/10. Compared with the previous 3 methods, I prefer the last two solutions. System file checker may not work all the time. If something goes wrong, you need to fix it. Also, system restore does not work forever. For example, if you upgrade Windows 7/8 to Windows 10, you will find system restore points gone. But a system backup or disk image will work all the time. It’s the most reliable way to repair system files in Windows 7/8/10.

 If you do not have a backup, you can download free AOMEI Backupper or AOMEI OneKey Recovery and then create a backup to get prepared for possible errors.