Quite often in Windows systems, you can observe the appearance of errors associated with damage or the absence of important system components that are extremely important for the operation of the OS. If system files are deleted by the user's own mistake or as a result of exposure to viruses and malicious codes, cardinal methods may be required to restore them. Do not rush to reinstall the system. This method is only good if none of the solutions below help.
Checking the integrity of system files in Windows 10: basic steps
The Windows OS family has evolved a lot - if you will, systems have gotten smarter. He alth recovery was first applied in the Millennium release. Then the decision concerned the creation of a backup copy, from which it was possible to boot. However, this option might not always work.

Today, Windows 10 system files can be restored after verification in several ways. This mainly concerns the use of the command console. However, the option of a standard rollback is also not excluded (naturally, provided that the user has not deleted saved checkpoints).
Restoring Windows 10 system files with the simplest method
First, consider the situation when the system does not boot due to critical errors. In this case, in theory, the recovery can start automatically. If this does not happen, you should force restart your desktop computer or laptop several times using a long press of the power button.
If the system gives a message that recovery is not possible, you will have to use the manual choice to load the Last Known Good Configuration. But in the tenth modification of the system, pressing the F8 button at the start of the download to call up an additional menu, as it was in earlier versions, does not work. Therefore, you will have to boot from the installation disk or flash drive with the transition to the recovery console, and only then choose to start the appropriate mode.

However, you can return the default setting quite simply, if you call the command line and enter the following combination in it: bcdedit /set {current} bootmenupolicy legacy. After that, when restarting, it will be possible to use the keystrokeF8 to bring up alternative boot menu.
Safe boot and reset
It is quite possible that the Windows system files have not undergone critical changes, and the computer system can be booted into safe mode by selecting it from the menu described above.

Here you will need to go to the settings, select the update and security section, and then use the button to reset the computer in the restore point. By the way, you can also use special boot options there to gain access to additional start options if the use of the F8 key is not provided. In the start menu, the items to boot the system and go to the recovery tools will appear. As already clear, checking the integrity of system files in Windows 10 will be done by scanning a backup copy of the system itself and the registry. By and large, if the user assumes that there may be problems on the computer, a copy of the system registry can be created in advance using the export function in the appropriate editor.
Using a special recovery command
But the universal tool is still considered to be the command console, which is used to fix most problems and critical errors.

In particular, the sfc /scannow command allows you to perform a full scan of all system elements, and restore them if problems are found. At the same time, it does not matter at all from whichdevice is being loaded. The sfc /scannow command works both when starting from the hard drive and when booting from removable media. But in the first case, the prerequisite is to run the command console as an administrator.
Online Recovery
The online repair tool DISM.exe can be called no less effective. To run it on a computer, Internet access must be active. There are two options for using the DISM.exe tool.

On the one hand, sometimes only the recovery line is enough, which is shown in the image above. If an error is generated, you will first need to enter the command to scan the “he alth” of the computer. In any case, the correction will take place.
Missing library loading issues
If anyone does not know, operating system system files include a large number of dynamic libraries. Their damage or removal can also lead to the fact that the OS will start with violations.

In this situation, you can use the DLL Suite utility, which provides for checking the integrity of Windows 10 system files or any other system, after which the missing or damaged components will be loaded. Again, its use requires access to the Internet. The disadvantage of this application is that it can only be used on an OS that somehow boots (for example, in safe mode).
Using fixers
There is another category of tools commonly referred to as fixers. The most famous "native" utility developed by Microsoft's specialists is the Fix It! program, which, however, also works exclusively on a bootable system. And it is far from a fact that problems with system files will be fixed. The program can easily report that they are found, and their correction by automatic means is impossible (the user will have to do it himself).
If you need to boot from removable media with subsequent verification and recovery, it looks much more appropriate to use the appropriate applications from Acronis. Fortunately, you can find quite a lot of them.

Now a few words about the situation when the Windows 10 system file integrity check revealed corruption at the level of boot records. Here, apart from a special tool of the OS itself, nothing will help. This is the Bootrec.exe executable file launched through the command console, for which you need to enter additional parameters and attributes separated by a space: "/FixMBR" and "/FixBoot" (without quotes).
If restoring the bootloader with this method is impossible, the full rewrite command "Bootrec.exe /RebuildBCD" can really help. But this tool works almost always (with rare exceptions, when viruses have firmly established themselves in the system).
Conclusion
To summarize, it can be noted thatthe use of each of the above methods for restoring the he alth of Windows 10, if the problems consist precisely in damage to system files and components, depends solely on the current situation. In some cases, a normal rollback helps, sometimes command-line tools work, in some cases, additional loading of deleted or damaged components works. Online recovery does not always work. At the very least, if the system can be booted safely with network driver support, there will be no problems. In the case of starting from removable media, no one will guarantee an Internet connection. However, you can try all methods. Perhaps at least one of them will help. It is clear, after all, that this will save the user from having to reinstall the OS (and this process is quite lengthy, since during installation it may be necessary to download updates, which can take several hours). Yes, and installed user programs will be deleted. Therefore, before making such a drastic decision, you should first try out the techniques outlined above.
However, the applied solutions are not a dogma. And it is not necessary to follow them exactly in the order in which they were described. It's likely that the Shell Toolkit will give you immediate results (it's the most commonly used, by the way). But the use of other methods cannot be ruled out. You never know…