How to Repair Corrupted Files in Windows using SFC

If your Windows PC is running slow, showing error messages, or crashing unexpectedly, corrupted system files might be the reason. Fortunately, Windows includes a tool called System File Checker, commonly referred to as SFC, that can scan and repair damaged system files automatically.

This guide explains how to repair corrupted files in Windows using SFC, including when to use it, what to expect during the scan, and what to do if problems persist. I’ve used this method on many computers over the years and it’s one of the first things I check when a system starts acting up.

What Is SFC?

SFC stands for System File Checker. It’s a built-in Windows utility that scans your system files for corruption or changes and replaces them with the correct version from a secure system cache. It’s available in all modern Windows versions, including Windows 10 and Windows 11.

When to Use SFC

Use SFC if you experience any of the following:

• Frequent crashes or system freezes
• Unresponsive apps or features not working
• Missing system components or broken Windows interface
• System errors after a failed update or malware infection
• Blue screen errors or unusual messages on startup

SFC does not affect your personal files. It only works with protected system files like DLLs, drivers, and essential components that Windows relies on.

Step-by-Step Guide: Repairing Files with SFC

Step 1: Open Command Prompt with Admin Rights

You’ll need administrator privileges to run SFC. Here’s how to open it correctly:

• Click the Start button or press the Windows key
• Type “Command Prompt” in the search box
• Right-click the result and choose Run as administrator
• If a permission prompt appears, click Yes

Now, a black command window will open. You’re ready to begin the scan.

Step 2: Run the System File Checker Tool

Once the command window is open, type the command to begin the system scan. The scan will check the integrity of Windows files and attempt to repair any that are corrupted.

After entering the command, press Enter. The system will begin scanning all protected files. This process usually takes 10 to 30 minutes depending on your system speed.

Step 3: Wait for the Scan to Finish

You’ll see progress messages on the screen. It’s important not to close the window or shut down your computer while the scan is running. Be patient and allow it to finish completely.

When done, you’ll see one of several possible messages:

• No integrity violations found – This means your system files are healthy.
• Corrupt files found and successfully repaired – SFC fixed the problems.
• Corrupt files found but some couldn’t be repaired – You’ll need to take additional steps.

What to Do if SFC Can’t Fix Everything

If the SFC tool reports that it found issues it couldn’t fix, it means the system file cache it relies on may also be damaged. In that case, the next step is to use another Windows tool called DISM, which stands for Deployment Imaging and Servicing Management.

DISM checks and repairs the underlying Windows system image. Once that’s repaired, you can run SFC again to fix any leftover problems.

To use DISM, follow these steps:

• Open Command Prompt as an administrator again
• Use the command to start a health restore of the Windows image
• Wait for it to finish (it might take 15 to 30 minutes)
• When complete, restart your computer
• Run the SFC scan again using the same steps as before

This often resolves stubborn corruption issues that SFC alone couldn’t fix.

Optional: View Detailed Repair Logs

If you’re curious about what exactly was scanned or repaired, Windows keeps a log file of the process. You can find it in the Windows folder under the Logs subfolder, named CBS.log.

To make the log easier to read, you can extract just the relevant entries related to SFC and save them as a separate text file. This is useful for advanced users or support technicians who want a deeper look at system behavior.

Tips from My Personal Use

As someone who frequently helps others with slow or misbehaving Windows systems, I always include SFC in my initial troubleshooting steps. It’s non-destructive, doesn’t require third-party tools, and works even when you don’t know exactly what’s wrong.

In my experience, running SFC often resolves issues related to broken Start menus, failed updates, or apps not opening. When paired with DISM, it can fix deeper system-level damage without needing to reset the entire PC.

When to Consider Other Options

If SFC and DISM both fail, or if your system continues to behave strangely:

• Try System Restore to roll back to a previous point
• Perform a repair installation of Windows using the Media Creation Tool
• As a last resort, back up your data and do a clean installation

These steps are more involved but may be necessary if corruption is severe.

Conclusion

Running System File Checker (SFC) is one of the simplest and most effective ways to fix corrupted files in Windows. Whether you’re troubleshooting a slowdown, recovering from malware, or just trying to keep your system healthy, SFC is a tool you should know how to use. It takes just a few steps, doesn’t require any downloads, and can save you from more serious problems down the line. If it doesn’t solve everything, DISM gives you a second line of defense. Make it a habit to run these scans when your system starts acting up. It’s a small task that can make a big difference in system stability and reliability.