Windows 7 - SFC /SCANNOW Command - System File Checker

You can run it from the GUI (Option 1 of previous link) or command prompt (Option 2).

question...
sfc flags a file - where do you get a new file from? you would think install.wim, but what if a hotfix replaced the file with a newer one? how do you know?

Hello atomMan,

This can show you how to extract a copy of the file from your retail Windows 7 installation DVD to use to replace the corrupted one.

Extract Files from Windows 7 Installation DVD

Hope this helps,
Shawn

hi Brink - i know how to extract the files. my question is how do you know the file you're extracting is the right version?

for instance, if a hotfix replaced explorer.exe, and maybe i hack explorer and ruin it, obviously replacing explorer.exe from setup/install.wim would replace the wrong version. what is to prevent this? i guess what i'm looking for a list of all files replaced by all hotfixes - just haven't found it yet

The only true way to know what the file versions are is to check the "Details" tab in the file's properties page to see if both the extracted and the one in the installation are the same or not.

The best way to avoid this is to create a restore point or system image before modifying any system files. This way you could easily use it to restore the file if something bad happens to it.


If you look up the KB number of the hotfix in the search box at the top of Microsoft Support, it will give you a complete list of files that it will effect. For example, KB2448827 for a IE9 update.

Hi Brink,

Another good tutorial. I just noticed a small typo in the Note box for Option 1:



You probably had a cold that day that you wrote it.....

Regards,
Golden

Thank you Golden.

LOL, oops. Corrected.

Hi Brink,
Tried sfc /scannow and sfc /verifyonly; at 19% both times I got this "Windows Resource Protection could not perform the requested operation".
Any suggestions?

Hello Henfracar, and welcome to Seven Forums.

Run a chkdsk C: /F command to see if you may have any bad sectors on the Windows 7 C: drive, then see if you may be able to run the sfc /scannow command afterwards.

If not, then you might see if you may be able to run sfc /scannow at boot or in safe mode.

Hope this helps,
Shawn

Hello Henfracar. Are you sure you ran SFC in an elevated command prompt? This Microsoft TechNet forum may be of some help.

SFC problem - "Windows Resource Protection could not start the repair service"