System File Checker

System File Checker

Infobox Software
name = System File Checker

caption =
collapsible =
author =
developer = Microsoft
released =
latest release version =
latest release date =
latest preview version =
latest preview date =
frequently updated =
programming language =
operating system = Microsoft Windows
platform =
size =
language =
status =
genre = Security software
license = MS-EULA
website = [ Microsoft SFC Documentation]

System File Checker is a utility in Microsoft Windows that allows users to scan for and restore corruptions in Windows system files. This utility is available on Windows 98, Windows 2000, Windows XP, Windows Server 2003, Windows Vista although in the Windows NT family of operating systems, it scans files using Windows File Protection.

In Windows Vista, System File Checker is integrated with Windows Resource Protection, which protects registry keys and folders as well as critical system files. Under Windows Vista, Sfc.exe can be used to check specific folder paths, including the Windows folder and the boot folder.

Windows File Protection worked by registering for notification of file changes in Winlogon. If any changes were detected to a protected system file, the modified file was restored from a cached copy located in a compressed folder at %WinDir%System32dllcache. In Windows Vista, Windows Resource Protection works by setting discretionary access control lists (DACLs) and access control lists (ACLs) defined for protected resources. Permission for full access to modify WRP-protected resources is restricted to the processes using the "Windows Modules Installer service" (TrustedInstaller.exe). Administrators no longer have full rights to system files.


Due to problems with Windows applications being able to overwrite system files in Windows 95, Microsoft has since implemented a number of security measures to protect system files from malicious attacks, corruptions, or problems such as DLL hell.

s; therefore, no preventive or reactive measure was available.

All Windows NT-based operating systems since Windows 2000 introduced real-time file protection, called Windows File Protection (WFP). [cite web
work=Help and Support
title=Description of the Windows File Protection Feature

In addition, the System File Checker utility (sfc.exe) was reimplemented as a more robust command-line utility that integrated with Windows File Protection. Unlike the Windows 98 SFC utility, the new utility forces a scan of protected system files using Windows File Protection and allows the immediate silent restoration of system files from the "DLLCache" folder or installation media.

In Windows Me, System File Checker was replaced with System File Protection (SFP). [cite web
title=System File Protection and Windows Me
] Similar to Windows File Protection, System File Protection offered real-time protection. The stand-alone SFC utility was removed and not available on Windows Me. [cite web
work=PC World
title=Answer Line: Windows 98 Utilities Missing in Windows Me?


Older versions of System File Checker are known to override patches distributed by Microsoft. This problem has since been rectified in the newer version of System File Checker. [cite web
work=Help and Support
title=The SFC /SCANNOW Command May Overwrite Hotfix Files


In Windows NT-based operating systems, System File Checker can be invoked, using a command prompt, with the following command. sfc /scannowIf it finds a problem, it will attempt to replace the problematic files from the "DLL Cache" (%WinDir%System32Dllcache). If the file is not in the DLL Cache or the DLL Cache is corrupted, the user will be prompted to insert the Windows installation media or provide the network installation path. In Windows Vista and onwards, files are protected using Access control lists (ACLs), however the above command has not changed.

System File Checker in Windows Vista and later Windows operating systems can scan specific individual files. Also, scans can be performed against an offline Windows installation folder to replace corrupt files, in case the Windows installation is not bootable. For performing offline scans, System File Checker must be run from another working installation of Windows Vista or a later operating system or from the Windows setup DVD which gives access to the Windows Recovery Environment.


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • File Allocation Table — FAT (от англ. File Allocation Table «таблица размещения файлов») архитектура файловой системы, сейчас широко используемая в картах памяти фотоаппаратов и других устройств. Разработана Биллом Гейтсом и Марком МакДональдом в 1977 году[1].… …   Википедия

  • System Idle Process — Бездействие системы (System Idle Process) процесс ядра операционной системы семейства Windows, представляющий собой отдельный поток (или несколько потоков на многоядерных системах), работающий тогда, когда процессор не выполняет других потоков.… …   Википедия

  • File Allocation Table — For other uses, see Fat (disambiguation). FAT Developer Microsoft Full Name File Allocation Table FAT12 (12‑bit version) FAT16/FAT16B (16‑bit versions) FAT32 (32‑bit version with 28 bits used) Introduced …   Wikipedia

  • System Restore — Окно восстановления системы в Windows XP‎ Восстановление системы (англ. System restore) компонент операционной системы Windows (процесс rstrui.exe), предназначенный для восстановления работоспособности ОС путем отката (восстановления предыдущего… …   Википедия

  • System tray — Область уведомлений в Windows NT Область уведомлений (англ. notification area) или системный трей (англ. system tray, от англ. tray «поднос, поддон») элемент панели инструментов среды рабочего стола («панель задач» в Windows), используемый для… …   Википедия

  • Encrypting File System — The Encrypting File System (EFS) on Microsoft Windows is a feature introduced in version 3.0 of NTFS[1] that provides filesystem level encryption. The technology enables files to be transparently encrypted to protect confidential data from… …   Wikipedia

  • Distributed File System (Microsoft) — This article is about Microsoft s implementation of DFS. For general discussion of the concept and other implementations, see Distributed file system. Distributed File System (DFS) is a set of client and server services that allow an organization …   Wikipedia

  • Windows File Protection — (WFP) is a technology included in all Microsoft Windows operating systems beginning with Windows 2000 to prevent programs from replacing critical Windows system files. Protecting core system files prevents problems such as DLL hell with programs… …   Wikipedia

  • Common Log File System — (CLFS) is a general purpose logging subsystem that is accessible to both kernel mode as well as user mode applications for building high performance transaction logs. It was introduced with Windows Server 2003 R2 and included in later Windows OSs …   Wikipedia

  • Comparison of file comparison tools — Contents 1 General 2 Compare Features 3 API / Editor Features 4 Other features 5 Aspects …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”