Summary: The System File Checker is a little known utility that validates that Windows own files are undamaged. It's a simple to run command line program.
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What is the System File Checker, and how do I run it? |
Windows XP works very hard to maintain the integrity of the system files on your machine. If you try to replace one of the "protected" files, you may get an informative message that the operating system has put the old approved version back. Not all files are under system file protection and even for those that are, there are ways around it. Occasionally system files become corrupt.
Enter the SFC, the System File Checker.
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SFC is a good utility to run when you suspect that system files have been somehow corrupted. It validates the digital signatures of all of the Windows system files and restores any that it finds are incorrect. It will use the on-disk cache if possible, but SFC may require that you provide your original installation CD or a location with an image thereof. (See this prior article about not having an installation CD on some of the alternatives if that's the case.)
To run the system file checker press Start, Run, and then type in SFC, followed by its options.
The most common usage of SFC is this:
SFC /scannow
This causes SFC to scan your system immediately. SFC can take a few minutes to run. As I said above, have your installation CD or equivalent available in case SFC needs to replace a damaged file.
While it's not documented anywhere, if SFC replaces any system files, I'd reboot. I just like to make absolutely certain that the file replacement actually takes effect.
The Microsoft knowledgebase includes more detailed SFC documentation, including more options to check at boot time, control the size of the system file protection cache, and so on. Speaking of which, the knowledgebase also includes System File Protection documentation, covering the mechanism Windows XP uses to keep your system files safe automatically.
UPDATE: If you have no CD, but you do have an I386 directory or CD image somewhere, check out this article: How do I tell Windows where my I386 folder has moved? Once you make the changes therein, you should be able to run SFC to completion.
Related:
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How do I tell Windows where my I386 folder has moved? You can move the I386 folder, but in order to keep Windows File Protection happy, you'll need to update a registry key as well.
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When I use Start-Run and type in a command, why does a window just flash and disappear? Start-Run, or the Run item on Windows Start menu is a way to run any program on your machine. Some will work as expected, but Start-Run of others just produces a quick flash. We'll look at why, and what to do instead.
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I have no CD - how do I get at Windows XP setup? If you don't have your Windows installation CD there are still a few things you can do. If you have an image of your CD, you may be able to do more.
Article C1896 - February 28, 2004
I am using what I think is Windows 2009. I moved from Texas to Louisiana and suddenely my midi file folder in outlook express has disappeared. It contains midis that I have collected for years to send out with my emails. Can you tell me how to and/or where to find it along with instuctions.
Posted by: Mozelle at December 5, 2009 2:27 PMThank you very much,
Mozelle
Your Scannow fix worked great. The XP
Posted by: Ron at December 10, 2009 5:11 AMOe8 would not get to the email, giving
an "Oe has encountered problems, sorry"
useless message. Tried Sys Restore to
reboot but still not help. Tried the XP
Add/Delete Components without success.
The SFC did work. Thanks.
For all of you who get errors from trying to run from the disk, it is because the Windows CD is not updated to the proper version. Most likely, it is SP1, and you need to have an SP2 CD(or SP3, etc.). Google "slipstream Windows CD" and you'll probably find what you need. It tells you how to make your SP1 CD into a SP2.
Posted by: Don't Know What I'm talking about at December 11, 2009 1:44 PMHi Leo. I have real problem in that I lost Outlook Express when I inadvertently restored factory settings. Now, when I want to send pictures prompted by windows live, Outlook express box comes up, I enter the recipient's address, press send, and then I get an error message .. lots of stuff followed by No, Server Error:998 Error Number Ox800CCC33. Can you advise please. Thanks
Posted by: Jackie at January 14, 2010 3:34 AMJackie
I used the SFC /scannow and nothing happened, it didn't even give any kind of error nor message. Does that mean there is nothing wrong with my files?
Posted by: Rita at February 1, 2010 6:14 PM