It doesn’t work correctly, you can use the SFC command-line utility to recover damaged or lost system files.
When you start to notice random errors, problems during system startup, or problems with the performance of Windows components, it is likely that this condition is caused by damaged or lost system files.
Despite the fact that Windows 10 copes with the protection of files that are necessary for the normal operation of the computer, some applications, drivers, or even Windows updates can cause loss of system stability. Like previous versions of Microsoft systems, Windows 10 includes a system file checker (System File Checker, SFC), a compact but powerful command line utility that can scan for system integrity and replace damaged or missing files with the original version.
In this guide, we will present the steps for using the System File Checker (SFC) to automatically repair damaged system files while the operating system is running. We also discuss how to run the utility in Safe Command Line mode and how to manually repair damaged system files that caused problems.
Warning: before starting work with the SFC utility, it is recommended to make a full backup of the system or create a system restore point. In case something goes wrong, you can return the system to its original state.
The following command allows you to perform a full scan of protected files on your computer and fix files that cause problems during Windows 10.
Command line
Sfc / scannow
3. After the scan is completed, you will see one of the following messages:
- Windows Resource Protection did not detect integrity violations. This means that no corrupted or lost files were detected in the system.
- Windows Resource Protection cannot complete the requested operation. This message means that an error occurred while scanning and you need to perform offline scanning.
- Windows Resource Protection detected corrupted files and successfully restored them. See the CBS.Log WinDir% \\ Logs \\ CBS \\ CBS.log log for details. This message appears when the SFC was able to fix the problem. You can look at the magazine in order to get acquainted with the detailed information.
- Windows Resource Protection has detected corrupted files but cannot recover some of them. See the CBS.Log% WinDir% \\ Logs \\ CBS \\ CBS.log log for details. In this case, you need to manually fix the damaged files.
Tip: to fix all problems, you may need to go through the integrity check procedure about three times.
To view information about the operation of the integrity checker in the CBS.Log file, you need to create a readable copy of the file on the desktop:
1. Enter the Start menu in the search Command line, right-click on the link that appears and select Run as administrator.
2. Type the following command and press Enter
Findstr / c: ""% windir% \\ Logs \\ CBS \\ CBS.log\u003e "% userprofile% \\ Desktop \\ sfclogs.txt"
3. Open the sfclogs.txt file located on the desktop using the Notepad application. The file will contain detailed information about the system scan and the files that could not be restored.
Note:detailed information is available only when scanning in Windows 10, but not when running the utility in Safe Mode on the Command Line.
Sometimes, protected system files that need to be restored are already loaded into RAM during WIndows 10. In this case, you can use the system file checker to fix the detected problems during system startup.
- 1. Use the keyboard shortcut Windows + I to open the Settings application.
- 2. Select the “Update and Security” section.
- 3. From the menu, select the “Recovery” option.
- 4. In the "Special boot options" section, click the "Restart Now" button.
- 5. Select “Troubleshooting.”
- 6. Go to “Advanced Settings”.
- 7. Click “Command Prompt” to boot the computer in command line mode.
- 8. After the reboot, you will need to enter the user name and password.
- 9. You need to tell SFC where the Windows installation files are. At the command prompt, enter the following command to recognize the location of the Windows 10 files and partitions reserved by the system:
- 10. Type the following command and press Enter:
Note that in the example, the / offboodir switch is used to indicate the drive letter of the partition reserved by the system. In this case, this is drive C, and the / offwindir switch indicates the path to the Windows files, which in our case is D: \\ Windows.
It must be remembered that during boot of the computer in command line mode, the drive letters may be different, so you need to use the command shown in step 9. However, in most cases when working with Windows 10, drive D is used for installation, and drive C is reserved System Reserved partition
- 11. After the scan is complete, close the command prompt.
- 12. Click “Continue” to exit and boot into Windows 10 as normal.
How to recover system files manually in Windows 10
If the system file checker cannot fix one or more files, you will have to restore them manually.
Open the sfclogs.txt file to determine which files were damaged. Perform a normal search to find file locations or use the search engine for more information. Then follow the instructions below to replace the damaged files.
Tip: You can find working versions of system files on another computer with the same version of the operating system as on the source computer.
- 1. Enter the Start menu in the search Command line, right-click on the link that appears and select Run as administrator, because SFC requires device administrator privileges to run.
- 2. At the Command prompt, type the following command and press Enter:
Note: replace C: \\ Path-and-File-Name with the path of the damaged file. For example:
C: \\ Windows \\ System32 \\ appraiser.dll
- 3. Allow full access (administrator access) to the damaged files using the following command and pressing Enter.
- 4. Replace the problem file with a working copy, type the following command and press Enter:
Note: replace C: \\ Path-SOURCE-and-File-Name with the path and name of the working version of the file, and C: \\ Path-DESTINATION-and-File-Name must be replaced with the path and name of the damaged file. For example:
Copy D: \\ Files \\ appraiser.dll C: \\ Windows \\ System32 \\ appraiser.dll
- 5. Type “Yes” and press Enter to confirm the overwrite.
After replacing the file, you can enter the SFC / verifyonly command and press Enter on the command line to check the integrity of all system files to verify that the problem has been resolved. Additionally, if only some files have been fixed, you can check the integrity of each individual file using the sfc / VERIFYFILE \u003d C: \\ Path-and-File-Name command. For example:
Sfc /VERIFYFILE\u003dC:\\Windows\\System32\\kernel32.dll
Keep in mind that the system file checker can be used not only in Windows 10, but also in previous versions of the operating system. However, depending on the OS version, some functions may vary. At the Command prompt, enter sfc /? to view all available options.
Often, a computer user is faced with the fact that his PC starts to work slowly. It starts to “slow down” the launch and operation of some programs, although a window with a message and an error code did not pop up on the monitor. This requires checking Windows 10 for errors. Do not immediately “demolish” and reinstall the operating system. After all, the reason may lie in the change or damage to system files.
Often this can occur due to the influence of viruses and other malware, incorrect shutdown of the computer after work and other problems. It should be borne in mind that not all errors can be displayed on the screen, they quietly accumulate, interfering with the PC. In order to identify and eliminate them, you need to periodically conduct a full check of Windows 10 for errors. You also need to analyze the integrity of the system, registry, video card, hard drive and other vital computer elements.
Checking your hard drive for Windows 10 errors
The hard drive and its bad sectors in Windows 10 can mainly be checked in the explorer interface and through the command line. Moreover, the installation of any programs in this process is not required.
- Through "Conductor". This check is the main one and is performed by Windows 10 in automatic mode. Since it takes about 60 minutes in time, it is better to run disk defragmentation at night, since all disks are checked using it. IN "Explorer" (right mouse button) open it on one of the disks "Properties", then go to "Service" with pressing "Optimize".
- Using the command line. Using this method, you cannot restore order on the hard disk, as during defragmentation, but you can quickly restore data from damaged sectors. For this action, the Command line (Administrator) is opened and the chkdsk C: / F / R command is entered into it (F - automatic correction of found problems, R - data recovery attempt).
After checking drive C, you need to check all other drives for errors, replacing only the letter designation.
Checking RAM for Windows 10 Errors
Diagnostics of memory for errors can be done through the built-in Windows utility. To start it, you need to take the following steps:
After the test is completed, the PC will reboot and on the monitor after logging in the system will display information on checking the memory for Windows 10 errors. To familiarize yourself with the results (MemoryDiagnostics-Results) need to log in Windows Logs - System.
Checking the Windows 10 registry for errors
If the registry error is not resolved in time, then the consequences of its “life” in it may turn into a blue screen of death for the computer, or even a complete failure of the system to start. You can check the Windows 10 registry for errors through:
- Through the built-in utility in Windows 10, but it is more suitable for detecting critical registry errors. We launch Command Prompt (Admin) - enter the command scanreg / fix - Enter.
- Through CCleaner Computer Cleaner. After starting the utility, you need to make a transition to the "Registry" section, then "Search for problems" and after checking click on "Fix selected ...". To fix registry problems, use the "Fix selected" button.
Checking ssd drive for Windows 10 errors
An SSD disk can be checked for errors using the functionality of some relevant programs that will conduct a full test. Among them, attention should be paid to:
- It needs to be downloaded, installed and launched. She will scan the hard drive and give the test result. In the main menu you need to use the tab "Service".
- This free utility will identify all problems, because it is specially designed to analyze the health of an SSD drive.
In addition to these programs, you can also use SSD Life, DiskCheckup, and HDDScan.
Checking Windows 10 System and System Files for Errors
Windows 10 system files are checked for errors using SFC.exe and DISM.exe. Consider both options.
- SFC.exe. To run a command, you need to log in Command line on behalf of Administrator and type sfc / scannow - Enter. Next, a corresponding check will occur, in which errors in system files are automatically corrected. If you want to analyze a specific system file, use the sfc / scanfile \u003d ”command file_path.
- DISM.exe. Through Command Prompt (Admin) you need to run in turn such commands dism / Online / Cleanup-Image / CheckHealth, dism / Online / Cleanup-Image / ScanHealth, dism / Online / Cleanup-Image / RestoreHealth, each of which takes a certain period of time to check and troubleshoot system problems files.
Checking the video card for Windows 10 errors
To check the video card for Windows 10 errors, it is recommended that you take these steps.
- Press Win + R - enter command dxdiag - Enter.
- Will come up on the monitor “DirectX Diagnostic Tool” (you will be prompted to check the driver), click on "Yes" and then click on "Screen".
- If you see in the window "Note" list of identified errors, then they need to be eliminated and then the video card will have high performance. It should be borne in mind that a list of errors should not be present in this field, because otherwise these problems "slow down" the functionality of the video card.
You also need to know that this video card test was performed without load. Therefore, you need to do an additional check of the computer element, but with a load.
To do this, you can use the benchmark for the graphics card Furmark. It is completely free and it is very easy to download it from the official website of the developer. All procedures for checking the video card are carried out after its visual inspection for external damage.
The performance of the Windows 10 operating system depends on many factors and reasons. To avoid many malfunctions in it, which lead to disastrous results, you always need to conduct a full-fledged diagnosis on time.
With the help of many both built-in and downloaded utilities (also completely free), it is possible to identify and also eliminate serious errors in systems in the early stages. This can be completely done independently, without resorting to the services of an expensive specialist from a computer service.
If you are tired of constant crashes from the system, errors and other “troubles” with the computer in the process, then you need to more often diagnose its elements to identify very serious problems.
Indeed, some of them in the work may be completely invisible, but stacking one upon the other, these errors can cause great harm to your computer or laptop.
After installing a new massive program, you may get the impression that the system began to malfunction: system errors, lags appeared, periodically notifications of unclear contents appear. Such a situation may arise that by installing a new application, you thereby violated the integrity of the OS. In this case, you need to know how checking the integrity of system files in Windows 10, in order to protect the OS from subsequent problems. In today's article, we will talk about how this test is performed, and from what problems it will protect you.
In the top ten there are two mechanisms for checking the integrity of the system and protected file objects, as well as their automatic reconstruction to the working form, if any damage is found, these are SFC and DISM. In addition to them, it is possible to run the Repair-WindowImage key for the PowerShell system language, which uses the DISM mechanism in its work. As a rule, experts recommend using both of them in turn. This behavior can be explained by the fact that the list of files for testing has a number of profound differences. Below I will describe how to use both of these tools, as it is necessary for safe and comfortable work in Windows 10 OS.
Important Note: the actions described in the article will not cause system conflicts or critical errors in your OS, however, if you have previously performed any operations related to modifying the contents or completely replacing the system’s working objects, the reconstruction will cancel all previously performed operations.
How to use the SFC mechanism, which allows you to check file integrity and adjust file objects of Windows 10
Many users have already dealt with a key designed to determine whether system objects are complete and complete, sfc / scannow. By default, this key scans the HDD for the presence of Win 10 file protected objects in it and automatically adjusts them.
To run the previously designated command, you will need to use a console that works in admin mode. To start it, use the right click on the start button "Start" and select "Command line (administrator)" in the list. So, console mode is started, now we set the parameter in cmd-environment sfc / scannow and at the end press Enter.
After specifying the request indicated earlier, the OS testing will be put into effect, after which the errors found related to the lack of completeness relevant for the correction will be corrected accordingly, and if none of them are detected, a message will appear on the display informing you that the sought-after problems related to integrity were not found in the OS, which will give a positive impetus in order to try other search methods.
If you want to check the full form of not all file objects in the operating system, but only of one, specific object stored on the drive, use the key sfc / scanfile \u003d ”file_path”.
An important note about the functioning of the SFC key: this command is not able to correct errors of the full form found in the files involved by the OS in the current time period of the OS’s functioning. To solve this problem, the operating system has the option to run SFC in the restoration environment, and again through the console mode.
How to boot in Win 10 recovery mode and use the SFC command there?
In Windows 10, there are a number of boot methods in restoration mode. Here are a few of them:
- Take the disk with the operating system distribution kit and insert it into the laser drive, and then boot from it. In addition, the disk function can be performed by a USB flash drive inserted in the corresponding USB slot. When the boot from the disc or flash drive occurs, click on the “System Restore” control in the lower left area of \u200b\u200bthe display;
- burn the OS recovery disk onto the disc and boot from it;
- when the OS entry screen is displayed, click on the “On” icon bottom right of the display, then, while holding down the Shift button, click on “Reboot”.
When one of the options is activated, click on the menu item "Identification and correction of errors" -\u003e "Advanced options" -\u003e "Command line". If you have chosen the last of the options described above, you will also be required to indicate the admin password used in the OS.
If cmd mode is activated, use the following commands:
- list volume.
By entering the second of these parameters, a list of logical devices will be displayed. Pay special attention to the letters of devices reserved by the operating system and boot volumes. Since the recovery mode operates autonomously from the OS, the letters of volumes may differ significantly from those presented in the standard functional environment.
When you remember the letters that belong to the system boot volumes in the HDD structure, it’s worth asking a few more prompts on the command line:
- sfc / scannow / offbootdir \u003d C: \\ / offwindir \u003d C: \\ Windows \\
Here, volume C: is bootable, as we can see by looking at the last screenshot above. In your case, the boot drive letter may be different from what we got. As a result, the integrity check of system files in Windows 10 will be launched, but this time using the SFC key it will be possible to check even files occupied by the operating system, which we have been trying for so long. A check may take a good half hour or even longer. If you are worried that your computer may freeze, check the cursor during testing: if it blinks, then the verification procedure continues. When the process is complete, exit console mode and restart the PC.
Checking the integrity of system files in Windows 10 using the DISM utility
The DISM Win-image processing and scaling service provides the ability to identify and fix those problems with corrupted OS files that the es-es-si service could not detect. In addition to this, DISM should definitely be used if the SFC does not detect a violation of the completeness of file objects in the operating environment, but you are almost sure that they are still there.
To use DISM, run cmd mode again on behalf of the administrator, and then use the following requests:
- dism / Online / Cleanup-image / CheckHealth - allows you to get data on the status and possible damage to the composite services of the Win-environment. Moreover, this command does not carry out the verification itself, but only checks the values \u200b\u200bspecified earlier.
- dism / Online / Cleanup-image / ScanHealth - checks for malfunctions and completeness of component storage. This verification may take quite a considerable period of time, but it's worth it. It is also possible "freezing" of the procedure at an indicator of 20%.
- dism / Online / Cleanup-image / RestoreHealth - performs both testing and reconstruction of system objects of the OS. Like the previous command, it requires a significant amount of time and can stop in the process.
You can also use the DISM command in the PowerShell program environment activated in admin mode using the Repair-WindowImage key. As examples, we will give the following commands:
- Repair-WindowsImage –Online –ScanHealth - check the integrity of system files in Windows 10.
- Repair-WindowsImage –Online –RestoreHealth - testing and correction of damage.
As you can see for yourself, checking the integrity of system files in Windows 10 is a simple and straightforward procedure that even a novice can handle. Once again we recall that it is better to use all the mentioned tools in combination, and not separately. This will help to create the desired effect and achieve a certain result in the verification process.
The Windows operating system is much like a living organism, from which it follows that sometimes even the smallest damage or deletion of one or more of its files can lead to certain problems. The cause of the damage can be the actions of viruses, malfunctions in the software, a sudden power outage, errors when editing system libraries, and so on.
As a result, the user may encounter various errors when starting programs or the inability to install them, problems with system settings and even blue “death screens”. Therefore, when diagnosing problems, the first thing usually recommended is to check the integrity of the Windows 7/10 system files. At the moment there are two main methods of checking and restoring system files - using standard utilities Sfc and DISMrun through the command line or PowerShell console.
The second tool is more powerful and is usually used when the SFC is not able to cope with the task or its launch fails. There are also third-party programs designed for these purposes, but for the most part they duplicate the functionality of SFC and DISM, providing more convenient access to them through the use of a graphical interface. In critical cases, when neither SFC nor DISM help, the system or its individual components are restored using a previously created backup.
Using SFC
SFC utility or otherwise System files checker It is present in all versions of Windows since 2000, and is intended to check the status and restore system files. SFC can take several arguments, but in this case we are only interested in one. Checking and restoring Windows 7/10 system files with its help is performed as follows. Run as the administrator a command line or PowerShell console and run the following command:
sfc / scannow
The verification procedure will take some time. If at the end errors are found, the utility will offer to perform recovery of damaged files during the reboot of the computer. If the SFC says that it cannot recover files, make sure that you have disabled EFS and Bitlocker encryption, boot in safe mode, and then repeat the scan procedure.
To ensure maximum access to the file system, the procedure for recovering damaged Windows system files can be performed in a bootable environment. There are several ways to get into the recovery environment, but we offer the most universal one. Boot the computer from the Windows installation disc, and when the installation wizard appears on the screen, click Shift + F10. Since the drive letters are different in the boot environment, you need to identify the letter of the system partition. We execute the following commands:
diskpart
list volume
On MBR disks, the system partition will most likely have the letter D, and the “Reserved by the system” section will have the letter C. Knowing the volume lettering, close the Diskpart with the exit command and check:
sfc / scannow / offbootdir \u003d C: / / offwindir \u003d D: /
When the scan is complete, Windows will restart in normal mode.
DISM Utility
How to check the integrity of the Windows 7/10 system files if the method described above does not help or if different errors are issued when executing the commands? In this case, you can try to resort to a more powerful tool - utility DISM. We launch the command line with administrator rights and execute the following command:
dism.exe / online / cleanup-image / scanhealth
If the utility reports that the component store is to be restored, restore it with the following command:
dism.exe / online / cleanup-image / restorehealth
If errors occur during the execution of the commands, try restoring the component store using PowerShell launched with elevated rights by running the Repair-WindowsImage -Online -RestoreHealth command when the computer is connected to the Internet.
After the procedures have been completed, you can check sfc / scannow and see if errors are repeated. If yes, check if you have the “Windows Module Installer” service turned on, but in general it is advisable to do this in advance.
Manual recovery of damaged files
This method is used when it is impossible to recover damaged SFC files, but to use it, in any case, you will need the exact same operating system installed on another computer or virtual machine or a backup copy. To determine which files to restore, run the command at a command prompt:
findstr / c: ""% windir% / logs / cbs / cbs.log\u003e "D: /sfc.log"
Information about damaged files will be saved to a log file, in our case it is sfc.log to disk D. The contents of the file can be quite voluminous, look for blocks with the key phrase “Cannot repair” (failed to recover) in it with the corresponding scan date and time.
The attached screenshot shows that SFC could not restore the Asseccbility.dll file. The path to the unrecoverable file must be indicated in the same log. Copy the original file from another computer and manually replace the damaged one. At this stage, one often encounters problems, since the file may turn out to be either used by system processes, or the user will not have rights to it.
To obtain rights and replace such files, you can use the standard console utilities Takeown with parameter / f and icacls with parameter / grant administrators: f, but there is a simpler and more universal way - use any “live disk” with a built-in file manager, for example, Dr.Web LiveDisk. If the computer boots up, it’s even easier, just copy the original files to any folder convenient for you on its hard drive.
You can edit the bootable ISO image of the same Dr.Web LiveDisk in UltraISO by creating a folder in it and copying windows files into it.
Now consider how to recover Windows 7/10 system files using such a drive. After booting from the media, find your folder with files (in Dr.Web LiveDisk, the mount point is / cdrom), copy the original files to the clipboard, go to the destination directory of the folder win and replace them with damaged ones.
If the original files are on the Windows disk, look for them in the win location, in the section in which you placed them. This method is convenient in that it removes all the limitations of the Windows file system, allowing you to get exclusive access to it.
Using third-party applications
The development of special programs that would allow recovering damaged and deleted system files does not make sense, since all the necessary functionality is available in the system itself. However, there are tools that simplify access to regular tools using a convenient graphical interface. Such, for example, is Microsoft DaRT - A boot disk, which is a set of administrative tools, which also includes a module for scanning and restoring Windows system files. The procedure for such a check is presented in the screenshots below.
For a more convenient start of the SFC, there are also programs Windows repair and, only unlike Microsoft DaRT, they start from the working system.
In Windows Repair, to start the check, go to the Pre-Repair Steps section, click on the tab “Step 4 (Optional)” and click the “Check” button.
In Glary Utilities, go to the “Modules” tab, select “Tools” in the menu on the left and click “Restore system files”. In both cases, the standard console utility SFC will be launched.
Other ways
As for the question of how to recover completely deleted system files, everything should be clear anyway. If disk size permits, back up the system partition regularly, or at least do not disable system protection so that you can roll back to the previous one if something happens.
And the last thing I would like to draw attention to. If you downloaded and installed a custom assembly, be prepared for the fact that SFC will more than likely find corrupted files in it. The reason is very simple - collectors very often modify their images, replacing, for example, the original icons in libraries and more. Therefore, before you restore the original files, think about whether you really need it if the system does not experience problems.
Operating Systems
