What is the Difference Between SFC, CHKDSK, and DISM in Windows 10?
Which Windows Diagnostic Tool Should You Use - SFC, CHKDSK, or DISM?
- Windows computers may slow down over time and crash due to corrupted files. These can be either your personal files or the core components of Windows OS.
- You can use Windows built-in diagnostic tools CHKDSK, SFC and DISM to correct corrupted files of your Windows computer.
- All three tools work in different ways, so you should understand the differences between them and figure out which diagnostic tool you should use.
If you frequently face a system crash, screen freeze or the legendary BSOD – Blue Screen Of Death – on your Windows computer, certain registry files in Windows are likely corrupted.
These problems can be easily fixed with Windows 10 built-in diagnostic tools SFC, CHKDSK or DISM.
But which tool should YOU use first on your system? Let us first go through the difference between SFC, CHKDSK and DISM.
Each tool works differently, and it is important to know how they work. If you decide to use all three tools, it may take up to 24 hours to get effective results. To find out which tool is best for you, you should first understand the basic definitions of SFC, CHKDSK and DISM.
- SFC (System File Checker)
SFC checks for missing important files of your Windows operating system and restores them from the cache.
- CHKDSK (Check Disk)
CHKDSK scans your drive to find bad sectors and tries to fix errors in the file system.
- DISM (Deployment Image Servicing and Management)
DISM directly deals with faulty Windows images and repairs them by downloading actual replacement files from Windows’ online servers.
When You Should Use CHKDSK?
CHKDSK or Check Disk is the first step to start diagnosing your Windows system. It scans for errors in your computer’s file system and attempts to fix them locally. CHKDSK examines the integrity of disk partitions by looking for logical file system errors or corrupted entries in a volume’s Master File Table (MFT).
When your system shuts down suddenly, during a power outage or other incident, it is common to see incorrect entries in the file system of your OS. These can be caused by an incorrectly set timestamp or an incorrect file size entry. Such entries can create bad sectors in your drive, causing your system to slow down or crash frequently. CHKDSK looks for such errors and tries to fix them.
However, in some cases, CHKDSK only informs the user about the problem and does nothing to fix it. This happens when CHKDSK considers the error to be severe or critical. Negligence and repeated overwriting to existing bad sectors are the reason why your hard disk gets into such a bad state that CHKDSK cannot fix.
Here are two easy ways to run CHKDSK on your Windows computer
1. Run CHKDSK through File Explorer
You can run CHKDSK on your computer from Windows File Explorer in this manner.
- Open File Explorer on your Windows machine. You can use the keyboard shortcut Windows + E for the same.
- Click on This PC and Right Click on the drive where you want to run CHKDSK.
- Click on Properties > Tools > Error Checking > Check
You may get a prompt where Windows says that you do not need to scan this drive. This is because Windows thinks that your drive is completely fine, and a CHKDSK scan is not required. However, if you still wish to run CHKDSK, click on Scan Drive.
CHKDSK can take anywhere between one minute to over two hours or more, depending on the type of storage or the size of the disk. It is generally faster on SSDs, and slower on HDDs as per the META. Once the scan is complete, CHKDSK will report any errors if scanned under the radar. Else it will just show you No errors were found.
2. Run CHKDSK from the Command Prompt
You can also run CHKDSK on your Windows computer through the Command Prompt. Alternately, you can use the same process mentioned below in Windows Powershell too.
1. Search for CMD on your Windows computer, you can use the keyboard shortcut Windows + S or simply press the Windows key to open the search bar.
2. Now Right Click on Command Prompt, and select Run as administrator option.
3. In the cmd terminal, type chkdsk (space) drive letter. For example, if you want to run CHKDSK on your C: drive, then type
Now hit Enter on your keyboard.
This will run CHKDSK on your computer in a Read-Only mode. If you want the CHKDSK tool to fix the issues on its own, then use these CHKDSK commands.
To fix problems scanned by CHKDSK automatically, type.
chkdsk /f c:
To scan errors and bad sectors, type
chkdsk /r c:
Here, c: stands for the drive name, which is the alphabet assigned to your drive.
Running CHKDSK through the Command Prompt takes the same amount of time running it through the Windows File Explorer.
CHKDSK shows “the volume is in use by another process”
This happens because while running CHKDSK, it has to be the only tool accessing the drive at that instance. In such cases, Command Prompt will ask you to reschedule the scan after a restart. You can also try manually closing all other programs on your computer to fix this error.
When You Should Use SFC?
SFC or System File Checker scans for all the system files in Windows, including protected files to see if they are corrupted are not. If SFC finds any corrupted system files in Windows, it will replace those damaged files using a cached copy. These cache files are placed in a compressed folder in Windows itself, and SFC will selectively replace those corrupted files with a copy obtained from the cache.
The OS saves a cached copy in a vault folder when protected files are modified in Windows as a backup. SFC makes use of these cached files, effectively replacing the corrupt files with their original state. This is an effective way to repair system files.
SFC can also repair errors in registry data. It uses the same concept of replacing modified files with cached copies. Microsoft introduced SFC first in Windows 98 to prevent problems faced by users when critical system files were modified to an extent where the OS becomes unstable to use. If your computer crashes frequently, or you face the Blue Screen Of Death quite often, running SFC can solve your problem.
How To Run SFC Scannow in Windows
1. Open Command Prompt as administrator by searching for CMD in the Windows search bar, Right Click on it and choose Run as administrator option.
2. You can either let SFC perform the fix on its own or run it in a Read-Only format,
3. For a full scan and automatic repair of corrupted files by SFC, type this command
If you wish to run SFC in Read-Only mode, then use this command
sfc /verifyonly command
In Read-Only mode, SFC will only notify the user about the errors in the file system and will not attempt to fix them. The user can later fix those issues on their own, or run the sfc /scannow command again to let SFC fix those problems.
After a successful SFC scan, you will get either one of these three results.
1. Windows Resource Protection did not find any integrity violations
This means that your system does not have any corrupt or missing files. The file system is normal.
2. Windows Resource Protection found corrupt files and successfully repaired them
This result means that SFC was able to identify errors in your system and has fixed them. Therefore, no further action is required from the user in this case.
3. Windows Resource Protection found corrupt files but was unable to fix some of them
If you get this result, it means that SFC could diagnose the issues in your system but failed to fix them. You can try repeating an SFC scan, which may fix the problem. However, if the issue persists, you will have to run a DISM scan on your Windows computer.
When You Should Use DISM?
DISM stands for Deployment Image Servicing and Management. It is the most advanced scan in Windows, and we recommend using it only if CHKDSK and SFC do not work for you. DISM is a command-line tool that services Windows images and key parts of Windows recovery and setup.
DISM can be considered as a virtual disk with the operating system loaded in itself. It scans the core files of your operating system to check for misbehaving files. DISM may require an active internet connection for its complete functionality (CHKDSK and DFC do not require an internet connection).
DISM tool is the ultimate solution for your system crashes as it targets the operating system directly, including admin privileges. In most cases, DISM will fix all the critical issues and pave the way for SFC and CHKDSK to function normally. It is recommended to run a CHKDSK and an SFC scan after a successful DISM scan.
How to run DISM in Windows?
1. Open Elevated Command Prompt in administrator mode on your computer.
2. Enter these DISM commands to check the status of your drive. This step gives us an idea of whether the core components of your drive are corrupted or not.
Dism /Online /Cleanup-Image /CheckHealth
3. After this step, if DISM does not detect any corruption, then we can proceed to check the health of your drive for an advanced DISM scan by typing the command given below
Dism /Online /Cleanup-Image /ScanHealth
4. If this step returns with an error, then rerun the same command. This time, DISM will try to fix the issues by connecting to Windows servers and downloading the required files to fix the problems in your OS. This process may take around 15-20 minutes.
5. Once done, we need to apply these fixes to the operating system permanently. For that, type the command given below and hit Enter on your keyboard.
Dism /Online /Cleanup-Image /RestoreHealth
After successful completion of all the above steps, you are required to restart your Windows computer.
Note: You recommend running a CHKDSK and an SFC scan on your computer after conducting a DISM scan. Use the same steps mentioned above to run CHKDSK and SFC. This will ensure that your system is free from technical errors in the OS.
I am still facing issues after running all – SFC, CHKDSK, and DISM, what to do?
If your system continues to crash or return with Blue Screen Errors at random intervals even after running CHKDSK, SFC, and DISM, then the best solution is to install Windows again on your computer freshly. Although we would never want you to go through all this, sometimes the best solution to fix unrepairable issues is downloading Windows and re-installing it.
FAQ on the difference between SFC, CHKDSK, DISM
Here are some frequently asked questions on Windows Diagnostic Tools and storage drives.
CHKDSK takes around 1-2 minutes to run. An SFC scan consumes over 5-10 minutes to complete. DISM scans usually take longer to complete as it requires downloading files from external resources. These time durations are also subject to your computer's drive speed (how fast your hard drive is). Your mileage may vary depending on the type of storage. For example, hard drives will take much longer than SSDs to complete the scans.
Windows does run CHKDSK automatically at boot at regular intervals, but it is a good habit to run CHKDSK manually on your computer once a month. This way, you would be able to monitor your drive closely, which would increase the life of the drive and keep your system stable.
If you have a hard drive, you should run disk defragmentation on your computer to improve the efficiency of the drive. Here's a guide on how to keep your hard drive healthy. If you have an SSD, then you should consider disabling drive indexing and hibernation. This will ensure that smaller chunks of data do not spread over multiple cells, easing the controller's workload present on your SSD.
SFC is a tool for repairing common Windows files and system structures. SFC will scan the integrity of all protected operating system files, including those that are not on your hard drive. It should be used before running DISM.
SFC will scan the integrity of all protected operating system files, including those that are not on your hard drive.
It is safe to use SFC /Scannow, but you should know that if there are any problems found in the scan, they will be displayed as warnings and errors. Errors should be corrected before running the tool again. If you are using Windows 10, SFC /Scannow will not be able to repair some types of problems unless you have the latest updates installed.
CHKDSK is a scanning tool for errors and bad sectors on the disk. It does not repair system files, but it can detect bad sectors on a hard drive that could cause data loss. To repair system files, you should run the SFC command.
Yes, you can run DISM and SFC at the same time. However, running these two tools simultaneously can cause system errors to occur as they will be trying to fix problems that are not necessarily there. If you are looking for a quick fix, running the two tools simultaneously is not recommended as it can introduce new errors on top of what was originally being fixed.
As an alternative, you can run DISM and SFC one at a time to avoid any errors.
SFC /scannow is a utility in Windows that can scan for and repair issues with the file system. It does not replace regular maintenance, which includes running Disk Cleanup to remove unnecessary files and defragmenting the hard drive.
SFC is usually only used when you suspect a system file has been modified. It doesn't hurt anything to run SFC, but it's usually not necessary.
Yes, you can run CHKDSK and SFC at the same time. Chkdsk checks for file system errors while running and then fixes them if found. SFC scans the system files and replaces bad or missing ones with original Microsoft versions.
There is no need to restart after running SFC Scannow, as the scan takes a few minutes and does not have any reboots. Sfc scans and fixes any corrupted or missing system files on your computer, but if it finds anything that needs to be fixed it will only do so when you restart your computer.