Windows Me System File Protection (SFP)

System File Protection (SFP) is a feature of Windows Me which was first introduced in Windows 2000 as Windows File Protection (WFP). SFP prevents the replacement of certain monitored or protected system files. By preventing the replacement of essential system files, file version mismatches can be avoided. SFP runs in the background.

SFP should take away one of the biggest headaches for users of Windows 9x systems: Poorly written application (installers) overwriting key system files with incompatible versions.

The way SFP works is amazingly simple: It monitors a database of protected files, while having access to the same files on a hidden location on the hard disk. If one of the protected files is deleted or replaced by an older version (or a version not approved by Microsoft), SFP will copy the original version of the file from the hidden location. The process runs without user intervention, and SFP does not display an error message or any other type of message during this process.

There is a way to enable SFP to give you Popup Notification. To do this you need to edit the registry:

Start the Registry Editor
Go to HKEY_LOCAL_MACHINE \ Software \ Microsoft \ Windows \ CurrentVersion \ SystemFileProtection
Double-click on the ShowPopups value, and change the value from 0 to 1
Close the Registry Editor and restart Windows

SFP maintains a log of all protected files that have been replaced. The log file, Sfplog.txt, can be found in the \Windows\System\SFP folder. If there are any entries in the log file (other than the log entry that is added when Windows first starts), then SFP had to protect some files.

You can view the list of files protected by SFP (nearly 900 files) by viewing Filelist.xml which is found in \Windows\System\Restore\.

If you want to determine if a particular file is being protected by SFP, you can do so using this method:

Double-click the Sfpdb.sfp file located in the \Windows\System\SFP\ folder
In the Open With dialog box, click WordPad, and make sure that the Always use this program to open these files check box is unchecked, then click OK
Click Find on the Edit menu (in WordPad)
Type the name of the file you want to check for SFP protection, and then click Find Next
If the file is found, the file is protected by the SFP feature. If you receive a WordPad has finished searching the entire document message, without finding the file, the file is not protected

It could be necessary to replace a protected file in Windows Me. Only the latest Windows installers are SFP aware, so it is possible that you may need to circumvent SFP. For more information, see Microsoft Knowledge Base Article 265371.

You can also find some aditional information on SFP in this Microsoft Support WebCast

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Windows Me System File Protection (SFP)

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