When your PC starts reporting errors, slowing down, or misbehaving, you can use Windows 10’s built-in diagnostic tools to try and fix the problem. CHKDSK, SFC, and DISM check the health of your hard drive and repair corrupt files, but the three tools work in different ways and target different areas of your system.

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CHKDSK, SFC, and DISM are system tools and you can run all three. But this can prove time-consuming and unnecessary for your specific problem. We’ll explain when and how to use this trio of troubleshooting tools.

When You Should Use CHKDSK

CHKDSK (Check Disk) is the first Windows diagnostic tool you should try if your PC starts acting strangely. For example, if it hangs while shutting down or becomes frustratingly slow.

CHKDSK scans your entire hard drive to find and fix errors in files and the file system itself. It also checks your drive for bad sectors (clusters of data that cannot be read) and either tries to repair them or tells your system not to use them.

Windows may run CHKDSK on startup if it detects a problem with your hard drive, sometimes for innocuous reasons such as improper shutdown, but also more serious ones including malware infection and impending drive failure. However, it won’t actually fix any issues until instructed to do so.

To prevent future errors and potential data loss, it’s worth running CHKDSK manually at least once a month as part of your PC maintenance routine. You can use one of the following methods:

1. Run CHKDSK through File Explorer

You can run CHKDSK from the command prompt. If you’re uncomfortable with using the Command Prompt, open File Explorer, click This PC, then right-click the drive you want to check and select Properties.

Select the Tools tab and then select Check in the Error checking section.

If Windows determines that everything is running smoothly, it will suggest that you don't need to scan the drive. To run CHKDSK anyway, select Scan drive.

The scan may take anything from a few minutes to half an hour, depending on the size and state of your drive. Once complete, CHKDSK will either tell you that no errors were found or if it does find any, it will suggest you fix them.

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7 Nifty CHKDSK Features to Use in Windows 10

CHKDSK ("check disk") is a Windows diagnostic tool that scans data drive volumes, verifies their integrity, and fixes errors when necessary. Here we highlight the improved CHKDSK features you can find in Windows 8 and 10.

 

When You Should Use SFC

Whereas CHKDSK finds and fixes errors in the file system of your hard drive, SFC (System File Checker) specifically scans and repairs Windows system files. If it detects that a file has been corrupted or modified, SFC automatically replaces that file with the correct version.

Knowing when to use SFC is usually more obvious than with CHKDSK, which depends on a hunch that your hard drive isn’t behaving correctly. If Windows programs are crashing, you’re getting error messages about missing DLL files, or you’re experiencing the dreaded Blue Screen of Death, then it’s definitely time to run SFC.

Open an elevated Command Prompt, by running the tool as an administrator. Then type the following and press Enter:

sfc /scannow

SFC will perform a full scan of your system and repair and replace any files that are damaged or missing, using versions from the Windows component store. The scan can take some time, but make sure you leave the Command Prompt window open until it’s complete.

If you only want to scan but not repair corrupted system files, type:

sfc /verifyonly command

Once SFC has finished scanning, you’ll see one of three messages:

  • Windows Resource Protection did not find any integrity violations. This means that whatever’s causing your PC problems isn’t related to a system file.
  •  Windows Resource Protection found corrupt files and successfully repaired them. This should hopefully mean that your problems have been solved.
  • Windows Resource Protection found corrupt files but was unable to fix some of them. This means that system files are to blame, but SFC can’t replace them. Try running the tool again in Safe Mode. If you still get the same result, don’t despair: it’s time to use DISM.
SFC scan for corrupt files

When You Should Use DISM

DISM (Deployment Image Servicing and Management) is the most powerful of the three Windows diagnostic tools. Although you shouldn’t usually need to use the tools, it’s the one to turn to when you’re experiencing frequent crashes, freezes, and errors, but SFC either can’t repair your system files or is unable to run at all.

While CHKDSK scans your hard drive and SFC your system files. DISM detects and fixes corrupt files in the component store of the Windows system image so that SFC can work properly. Create a backup of your drive partition before running DISM, just in case something goes wrong.

As with CHKDSK and SFC, you’ll need to open an elevated Command Prompt to run DISM. To save you the time and risk of performing repairs unnecessarily, you can first check if the image is corrupted without making any changes. Type the following command and press Enter:

Dism /Online /Cleanup-Image /CheckHealth
 
The scan should only take a few seconds. If no corruption is detected, you can run a more advanced scan to determine if the component store is healthy and repairable, again without making any changes, by typing:
Dism /Online /Cleanup-Image /ScanHealth
If DISM reports that there are problems with the system image, run another advanced scan to repair these issues automatically. DISM will connect to Windows Update to download and replace damaged files as required. Note that the process may take up to 10 minutes and hang for a while at 20 seconds, but this is normal. Type this command: 
Dism /Online /Cleanup-Image /RestoreHealth 
Once the scan and repairs are complete, restart your PC and run SFC again to replace your corrupt or missing system files.

Fight Corruption and Win

Now that you understand what CHKDSK, SFC, and DISM do, running one or more of these Windows troubleshooting tools will hopefully help you fix your PC.

If you’re still having trouble, perform a System Restore. This will restore your system files, settings, and programs to a time when they were working properly. If your system wasn’t damaged when the restore point was created, may solve your corruption problems.