Everyone already knows the basic usage of sfc in Windows XP, but the meaning of the parameters in the command line and the introduction in "Help and Support" are different, affecting to some extent The user's use, the following uses the meaning of the combination. 1. In the general media, when introducing the use of sfc, for example, input sfc /scannow to run sfc (system file check), but in fact, Windows file protection is always enabled, only when the Dllcache folder is damaged or It is necessary to use sfc /scannow, sfc /scanonce or sfc /scanboot to fix the contents of the Dllcache directory when it is not available. Tip: File Protection When you install software other than the operating system, you may overwrite some shared system files, such as dynamic link libraries (".dll" files) and executable files (".exe" files). After the coverage, the system may no longer be stable. Since Windows 2000, Microsoft has added file protection. Windows file protection prevents the protected system files from being replaced. Windows File Protection can detect attempts by other programs to replace or move <-- --> protected system files. If the file version is incorrect, Windows File Protection replaces the file from the Dllcache folder (also known as the file-protected cache, located in the system32 folder of the system directory) or the Windows 2000/XP installation CD. 2. Regarding the meaning of sfc /revert, for example, if you run sfc /scanboot, you will automatically run sfc every time you enter Windows XP, and you will not see it in the "Startup" of "System Configuration Utility". Traces, if you want to disable, you can run sfc /revert to restore it to the default state. 3. sfc /purgecache can clear the "Windows File Protection" file cache, which removes all the contents of the dllcache folder. This is of course possible for users with tight disk drives, but Windows XP has lost its ability to restore system files. , so the compromise should be to reduce the size of the folder appropriately, /cachesize=x parameter to set the size of the "Windows File Protection" file cache, the default size is 102M, the minimum is 15M, you can The situation setting, Windows will adjust according to the importance of the file (of course, you can also increase the folder). The meaning of other parameters will not be described again. 4. Disable file protection If you want to disable file protection, you can enter gpedit.msc in "Start → Run" as follows, and find "Windows File Protection" in "Local Computer Policy → Computer Configuration → Administrative Templates → System". Double-click "Windows File Protection Scan" in the right window, go to the "Settings" tab, select "Disabled", here you can also set the scanning frequency of file protection and specify the location of the cache.