What is the SFC tool and how can it be used to identify files that may need manual replacement?

What Does System File Checker (SFC) Mean?

System File Checker (SFC) is a Windows 10 utility that helps administrators to check for file corruption. The executable utility may help to repair registry data. System File Checker is a feature of modern Windows operating systems including Windows 10, Windows 8, Windows 7 and Vista.

Inhaltsverzeichnis Show

What Does System File Checker (SFC) Mean?
Techopedia Explains System File Checker (SFC)
When You Should Run These Commands
Run the SFC Command to Repair System Files
Run the DISM Command to Fix SFC Problems
Try a System Restore or System Reset Next
What can be used to repair common causes of bootable operating systems?
What is the last thing that occurs in the Windows 7 boot process before the Windows desktop appears?
What command can be used to scan for Windows installations not stored in the BCD?
What is the name of the program that reads the settings in the boot configuration data BCD file and manages the initial startup of the OS?

Techopedia Explains System File Checker (SFC)

With System File Checker, users can open a command prompt window and trigger a system scan that shows whether protected system files may be corrupted. Microsoft recommends not closing the command prompt window until completion of the scan.

System File Checker may return one of several messages – for example, System File Checker may say that the utility did not find integrity violations. System File Checker may say that the system could not perform the operation. The utility may also indicate that the system found corrupt files and repaired them. If System File Checker is not able to fix corrupted files, users can go in and replace them manually.

The System File Checker tool built into Windows can scan your Windows system files for corruption or any other changes. If a file has been modified, it will automatically replace that file with the correct version. Here’s how to use it.

When You Should Run These Commands

If Windows is experiencing blue-screen or other crashes, applications are failing, or some Windows features just aren’t working properly, there are two system tools that might be able to help.

RELATED: Everything You Need To Know About the Blue Screen of Death

The System File Checker (SFC) tool built into Windows will scan your Windows system files for corruption or any other changes. If a file has been modified, it will automatically replace that file with the correct version. If the SFC command doesn’t work, you can also try the Deployment Image Servicing and Management (DISM) command on Windows 8, 10, or 11 to repair the underlying Windows system image. On Windows 7 and earlier, Microsoft offers a downloadable “System Update Readiness Tool” instead. Let’s take a look at how to use them.

RELATED: How to Scan for (and Fix) Corrupt System Files in Windows

Run the SFC Command to Repair System Files

Run the SFC command when troubleshooting a buggy Windows system. SFC works by scanning for and replacing system files that are corrupt, missing, or changed. Even if the SFC command doesn’t repair any files, running it will at least confirm that no system files are corrupted and then you can continue to troubleshoot your system with other methods. You can use the SFC command as long as the computer itself will start. If Windows will start normally, you can run it from an administrative command prompt. If Windows won’t start normally, you can try starting it in Safe Mode or in the recovery environment by booting from your installation media or recovery disc.

RELATED: How to Use Safe Mode to Fix Your Windows PC (and When You Should)

However you get to the Command Prompt — normally, Safe Mode, or recovery environment — you’ll use the command the same way. Just remember that if you start Windows normally, you will need to open the Command Prompt or PowerShell with administrative privileges. To do this, right-click the Start button and select “Command Prompt (Admin)”.

Note: On Windows 11, you might need to select “Windows Terminal (Admin)” instead of “Command Prompt (Admin)” or “PowerShell (Admin)”.

At the Command Prompt, type the following command and press Enter to run a full system scan and have SFC attempt repairs:

sfc /scannow

Leave the Command Prompt window open until the command completes, which may take some time. If everything is fine, you’ll see the message “Windows Resource Protection did not find any integrity violations.”

RELATED: How to Use Safe Mode to Fix Your Windows PC (and When You Should)

If you see a “Windows Resource Protection found corrupt files but was unable to fix some of them” message, try restarting your PC in Safe Mode and running the command again. And if that fails, you can also try booting with your installation media or recovery disc and trying the command from there.

Run the DISM Command to Fix SFC Problems

You shouldn’t normally have to run the DISM command. However, if the SFC command fails to run properly or can’t replace a corrupted file with the correct one, the DISM command — or System Update Readiness Tool in Windows 7 — can sometimes fix the underlying Windows system and make SFC run correctly.

To run the DISM command in Windows 8, 10, and 11, open Command Prompt, PowerShell, or Windows Terminal with administrative privileges. Type the following command and then press Enter to have DISM check your Windows component store for corruption and automatically fix any problems it finds.

DISM /Online /Cleanup-Image /RestoreHealth

Allow the command to finish running before closing the Command Prompt window. This may take five to ten minutes. It’s normal for the progress bar to stay at 20 percent for a while, so don’t worry about that.

If the results of the DISM command state that anything was changed, restart your PC and you should then be able to run the SFC command successfully.

On Windows 7 and earlier, the DISM command isn’t available. Instead, you can download and run the System Update Readiness Tool from Microsoft and use it to scan your system for problems and attempt to fix them.

Note: If you’re still using Windows 7, you’ll need to grab the right version of the Readiness Tool. The latest version available is “System Update Readiness Tool for Windows 7 for x64-based Systems (KB947821) [October 2014].” Download that one.

Try a System Restore or System Reset Next

If you’re still experiencing system problems and the SFC and DISM commands don’t help, you can try more drastic actions.

Running the System Restore tool will restore your Windows operating system files, settings, and applications to an earlier state. This may fix system corruption problems if the operating system wasn’t also damaged at the earlier point when the restore point was created.

RELATED: How to Use System Restore in Windows 10, 11, 7, and 8

An if all else fails, you could always resort to performing a system reset or reinstalling Windows. On Windows 8, 10, and 11 you can perform a “Reset this PC” operation to reset Windows to its default state. You’ll have the option to keep your personal files in place — though you’ll have to reinstall programs — or to remove everything and do a complete reinstall. Whichever you choose, make sure you’ve backed up your PC first! On Windows 7 and earlier, this will require using your computer’s manufacturer-provided recovery partition or reinstalling Windows from scratch.

If you encounter other errors while running any of the commands we’ve covered, try searching the web for the specific errors you encounter. The commands will often point you to log files with more information if they fail — check the logs for more details about specific problems. Ultimately, it may not be worth troubleshooting serious Windows corruption problems when you can just reset Windows to its default state or reinstall it. That decision will be up to you.

What can be used to repair common causes of bootable operating systems?

Windows Recovery Environment (WinRE) is a recovery environment that can repair common causes of unbootable operating systems.

What is the last thing that occurs in the Windows 7 boot process before the Windows desktop appears?

What is the last thing that occurs in the Windows 7 boot process before the Windows desktop appears? Userinit.exe applies Group Policy settings and any programs not trumped by Group Policy that are stored in startup folders and startup registry keys.

What command can be used to scan for Windows installations not stored in the BCD?

The bootrec command will search for Windows installations not included in the BCD and then ask you if you'd like to add one or more to it. You should see one of the following messages at the command line. Scanning all disks for Windows installations.