System File Checker is a utility in Windows that will allow you to scan and restore corruptions in Windows system files. This article describes how to run the System File Checker tool (SFC.exe) to scan your system files and to repair missing or corrupted system files. If a Windows Resource Protection (WRP) file is missing or is corrupted, Windows may not behave as expected. For example, some Windows functions may not work, applications such as Train Simulator or Train Sim World might not install properly or services the applications require for correct function may not work correctly.


Important Note:

This guide is technical in nature and should not be attempted if you:

  1.  Do not understand any of the terms used in this document;
  2.  Are not confident in your ability to carry out the instructions given.

If you are at all unsure of this, we would recommend you ask a local computer professional or someone you trust to do this for you.


How to Run the System File Checker:

  1. Open an elevated command prompt. To do this, do the following as appropriate:
  2.  
  3. If you’re using Windows 8 or 8.1
  4.  
  5. Swipe in from the right edge of the screen, and then tap Search. Or, if you are using a mouse, point to the lower-right corner of the screen, and then click Search. Type Command Prompt in the Search box, right-click Command Prompt, and then click Run as administrator. If you are prompted for an administrator password or for a confirmation, type the password, or click Allow.

  1.  
  2. If you’re using Windows 10 or Windows 7
  3.  
  4. Click Start, type "Command Prompt" or "cmd" in the Search box, right-click Command Prompt, and then click Run as administrator. If you are prompted for an administrator password or for a confirmation, type the password, or click Allow.


  1. At the command prompt, type "sfc /scannow", and then press ENTER.


The sfc /scannow command will scan all protected system files, and replace corrupted files with a cached copy that is located in a compressed folder at %WinDir%\System32\dllcache.


The %WinDir% placeholder represents the Windows operating system folder. For example, C:\Windows.


Note: Do not close this Command Prompt window until the verification is 100% complete. The scan results will be shown after this process is finished.


After the process is finished, you may receive one of the following messages:


  • Windows Resource Protection did not find any integrity violations. (This means that you do not have any missing or corrupted system files.)


  • Windows Resource Protection could not perform the requested operation. (To resolve this problem, perform the System File Checker scan in safe mode, and make sure that the PendingDeletes and PendingRenames folders exist under %WinDir%\WinSxS\Temp.)


  • Windows Resource Protection found corrupt files and successfully repaired them. Details are included in the CBS.Log %WinDir%\Logs\CBS\CBS.log. (To view the detail information about the system file scan and restoration, go to How to view details of the System File Checker process.)


  • 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.



To repair the corrupted files manually, view details of the System File Checker process to find the corrupted file, and then manually replace the corrupted file with a known good copy of the file.