Windows File Protection (WFP), a sub-system included in

Microsoft Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

s of the

Windows 2000 Windows 2000 is a major release of the Windows NT operating system developed by Microsoft, targeting the server and business markets. It is the direct successor to Windows NT 4.0, and was Software release life cycle#Release to manufacturing (RT ...

and

Windows XP Windows XP is a major release of Microsoft's Windows NT operating system. It was released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct successor to Windows 2000 for high-end and business users a ...

era, aims to prevent programs from replacing critical Windows system files. Protecting core system files mitigates problems such as DLL hell with programs and the operating system. Windows 2000,

and

Windows Server 2003 Windows Server 2003, codenamed "Whistler Server", is the sixth major version of the Windows NT operating system produced by Microsoft and the first server version to be released under the Windows Server brand name. It is part of the Windows NT ...

include WFP under the name of ''Windows File Protection'';

Windows Me Windows Me (Millennium Edition) is an operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It was the successor to Windows 98, and was released to manufacturing on June 19, 2000, and t ...

includes it as System File Protection (SFP).

Operation

With Windows File Protection active, replacing or deleting a system file that has no file lock to prevent it getting overwritten causes Windows immediately and silently to restore the original copy of the file. The original version of the file is restored from a cached folder which contains backup copies of these files. The

Windows NT Windows NT is a Proprietary software, proprietary Graphical user interface, graphical operating system produced by Microsoft as part of its Windows product line, the first version of which, Windows NT 3.1, was released on July 27, 1993. Original ...

family uses the cached folder .

caches its entire set of compressed cabinet setup files and stores them in the folder. WFP covers all files which the operating system installs (such as , , , etc.), protecting them from deletion or from replacement by older versions. The digital signatures of these files are checked using code signing and the signature catalog files stored in the folder. Only certain operating system components such as the ''Package Installer'' (Update.exe) or

Windows Installer Windows Installer (msiexec.exe, previously known as Microsoft Installer, List of Microsoft codenames, codename Darwin) is a software component and application programming interface (API) of Microsoft Windows used for the Installation (computer ...

(Msiexec.exe) can replace these files. Changes made using any other methods in order to replace these files are reverted and the files are silently restored from the cache. If Windows File Protection cannot automatically find the file in the cached folder, it searches the network path or prompts the user for the Windows installation disc to restore the appropriate version of the file. WFP integrates with the System File Checker () utility.

Windows Vista Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, released five years earlier, which was then the longest time span between successive releases of Microsoft W ...

and later Windows systems do not include Windows File Protection, but they include Windows Resource Protection which protects files using ACLs. Windows Resource Protection aims to protect core registry keys and values and prevent potentially damaging system configuration changes, besides operating system files. The non-use of ACLs in Windows File Protection was a design choice: Not only did it allow operation on non-NTFS systems, but it prevented those same "bad" installers from failing completely from a file access error.

References

External links

Overview of Windows File Protection

Registry settings for Windows File Protection

Whitepaper on Windows File Protection

Overview of System File Protection (Windows Me)

Hacking Windows File Protection

Effective Files Protection Tool
{{Windows Components Discontinued Windows components