Scanning and Fixing System Files

by Allen Wyatt
(last updated April 4, 2016)

2

Windows includes a helpful utility that can be used to scan your system files and determine if there are any problems with those files. Why might there be problems? Perhaps a system file was somehow damaged or it was replaced by malware or another errant utility program.

The utility program is named Windows Resource Protection and is available only from the command prompt, and then only if you are working in administrator mode. Assuming you can boot your system, you can press Win+X on the keyboard and then choose Command Prompt (Admin) from the available options. (This works in both Windows 8 and Windows 10. In Windows 7, click Start, search for "cmd", and then press Ctrl+Shift+Enter to run the command prompt in administrator mode.)

At the command prompt, enter the following:

sfc /verifyonly

The sfc command is what you use to start the Windows Resource Protection utility. (Why name the command "sfc" when "wrp" would have made more sense for "Windows Resource Protection?" I suspect that the command started out as meaning "system file check," which abbreviates to "sfc" very nicely.) The /verifyonly switch tells the utility to only check things out and not make any changes to the files. After completing the check (it can take a while) you'll get a report back about any problems discovered. (See Figure 1.)

Figure 1. The results of running the sfc command.

Had there been any problems discovered, you could then run the utility with a different switch:

sfc /scannow

This tells Windows Resource Protection to run and fix anything it finds wrong. There are also a whole lot of other switches you could use to modify how the command does its work. The switches available will differ based on the version of Windows you are using. To see what you have available, try this at the command line:

sfc /?

Earlier I mentioned that you can run the Windows Resource Protection utility from the command prompt "assuming you can boot your system." You should know that you can also run the utility from the command line provided if you start your system in Safe Mode or even if you are able to boot your Windows installation media in Repair Mode.

 This tip (198) applies to Windows 7, 8, and 10.

Author Bio

Allen Wyatt

With more than 50 non-fiction books and numerous magazine articles to his credit, Allen Wyatt is an internationally recognized author. He  is president of Sharon Parq Associates, a computer and publishing services company. ...

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Comments

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What is five minus 0?

2016-04-04 06:29:05

Rudy

A few minutes ago I entered a comment. Then I went back and _carefully_ read the directions. I had not used Ctrl+Shift+Enter to run the Command Prompt window.

I tried a second time, and sfc is now running.

Sorry for having caused any trouble.


2016-04-04 06:22:38

Rudy

I followed the directions and encountered the following message:

"You must be an administrator running a console session in order to use the sfc facility."

I am the only user of this machine, so I'm wondering why I'm not an administrator. I'm also wondering what a 'console session' is.


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