System File Checker is a utility in Windows that allows users to scan for corruptions in Windows system files and restore corrupted files. This page describes how to run the System File Checker tool to scan your system files and to correct missing or corrupted system files. If a Windows file is missing or is corrupted, Windows may behave unexpectedly. For example, some Windows functions may not work, or Windows may crash even in worst case.
Opening Command Prompt
As SFC requires scanning of system files,Administrative privileges are required in command prompt,better known as elevated command prompt.Use directions as per your OS:
Windows 10 and Windows 8
Press Windows key+X simaltaneously and you will get something like this
Press command Prompt(admin) and an elevated CMD would open.
Windows 7 and Windows Vista
a. Press “Windows Key” to open Start menu
b. Type “cmd” without quotes in the search box.
c. On the left pane, right click on the “cmd” option and select “Run as Administrator”.
STEP 2-Run SFC command
In the window that opens,type in SFC /SCANNOW to start scanning.
It might take time depending on speed of your system.
STEP 3: Analyzing the results:
When you have finished it will display either one of three:
Windows did not find any integrity violations (a good thing)-No corruptions found
Windows Resource Protection found corrupt files and repaired them (a good thing)-Corrupt files found but repaired
Windows Resource Protection found corrupt files but was unable to fix some (or all) of them (not a good thing)-Corrupt files found but not repaired
For the 3rd item,you can correct the corrupted files either using DISM utility that would require an Installation media to correct the files or you can get the good copy of the corrupted file from a computer running same OS .Refer to the DISM article.
To view the details of the System file checker process:
We can see which files were found corrupted using the file SFC generates.We can get the good copy of the file from any computer and replace the file in our system.
Open an elevated command prompt as described above.
At the command prompt, type the following command, and then press ENTER:
Note The Sfc.txt file contains details from every time that the System File Checker tool has been run on the computer. The file includes information about files that were not repaired by the System File Checker tool.
Now see the entry somewhat like this:Cannot repair member file XXXXX,the source file is also corrupted.
Correcting the corrupt files without DISM:
Take administrative ownership of the corrupted system file. To do this, at an elevated command prompt, copy and then paste (or type) the following command, and then press ENTER:
takeown /f Path_And_File_Name
Note The Path_And_File_Name placeholder represents the path and the file name of the corrupted file. For example, type takeown /f C:windowsopencl.dll
Grant administrators full access to the corrupted system file. To do this, copy and paste (or type) the following command, and then press ENTER:
icacls Path_And_File_Name /GRANT ADMINISTRATORS:F
Note The Path_And_File_Name placeholder represents the path and the file name of the corrupted file. For example, type icacls C:windowssystem32opencl.dll /grant administrators:F.
Replace the corrupted system file with a known good copy of the file. To do this, copy and paste (or type) the following command, and then press ENTER:
Copy Source_File Destination
Note The Source_File placeholder represents the path and file name of the known good copy of the file on your computer, and the Destination placeholder represents the path and file name of the corrupted file. For example, type copy E:tempopencl.dll C:windowssystem32opencl.dll.