The System File Checker is a very useful tool in Windows that allows you to check for and replace corrupted system files. However it does not list all the protected system files or allow you to check for a particular file individually, should the need arise.
System Files Lister is a small utility that enumerates all the files protected by Windows operating system, with the help of the Windows File Protection (WFP) feature.
Windows File Protection (WFP) prevents programs from replacing critical Windows system files. Programs must not overwrite these files because they are used by the operating system and by other programs. Protecting these files prevents problems with programs and the operating system.
WFP protects critical system files that are installed as part of Windows (for example, files with a .dll, .exe, .ocx, and .sys extension and some True Type fonts). WFP uses the file signatures and catalog files that are generated by code signing to verify if protected system files are the correct Microsoft versions.
Replacement of protected system files is officially supported only through the following mechanisms:
- Windows Service Pack installation using Update.exe
- Hotfixes installed using Hotfix.exe or Update.exe
- Operating system upgrades using Winnt32.exe
- Windows Update.
But at times, you may knowingly or unknowingly end up some system file. For example if you customize your Windows and replace your default Windows Start Orb with a custom start button, you end up replacing a system file.
The System File Checker can check for and replace corrupted system files. If System File Checker discovers that a protected file has been overwritten, it retrieves the correct version of the file from the cache folder, viz %Systemroot%\System32\Dllcache or the Windows installation source files, and then replaces the incorrect file.