There have been errors in the Windows operating system since its inception. They occurred in almost all versions. It looks different. An error message pops up, a "blue screen of death" is displayed, the application crashes or the system reboots altogether. In most cases, this is due to a violation of the integrity of system and important files. But the causes of such consequences can serve as a virus attack, as well as the general clogging of the system and failures.
Starting with Windows 2000, a mechanism was implemented inside it that made it possible to check the integrity of important files with the possibility of their recovery. The utility name is SFC. The best known application is SFC / scannow. What this command is and what it is used for will be described in detail in this article.
SFC / scannow - what is it?
In general, on the Internet, this bunch is used everywhere in instructions and the like. In fact, the expression following the slash is just the key or argument to the SFC utility.
SFC is a special program designed to check the status of system files in order to find distortions, integrity violations, or even their absence. You need to run it with certain arguments, a list of which will be presented below.
- SFC /? This key will list all available arguments with examples of their use. Actually, the same effect can be achieved by calling just SFC without prefixes;
- SFC / scannow. What is that key? It scans, calculates whether the system files have been changed, and if any are found, it starts recovery. The whole cycle will happen in default mode, i.e. user intervention after entering a command is not required. Sometimes the output of this procedure may display something like "SFC / scannow cannot restore some files." This means that the file is so damaged that it cannot be restored or is completely absent;
- / verifyonly. This argument simply checks the files without restoring them;
- / scanfile = Path to the file being checked. Scan and attempt to restore one specific file;
- / verifyfile = Path to the checked file. Similar to the previous command, only does not restore the found problematic instances;
Additional teams
- / offwindir = drive letter on which to scan. Provides the ability to verify integrity by specifying specifically where Windows is installed;
- / offbootdir = drive letter from which to restore files. This key is used in conjunction with scannow and the previous argument;
- / scanonce. This key sets the scheduled check for the next system restart;
- / scanboot. This argument, like the previous one, plans to scan, only now every time it reboots;
- / revert. This key cancels the applied changes during the execution of previous commands;
- / purgecahe. The argument deletes the source files from the special cache, by which the recovery occurs. At the same time, it is checked and filled with current ones, if their integrity is not violated;
- / cachesize = i. This key sets the cache size at the request of the user. The value of i in megabytes is measured.
Examples of using SFC / scannow. What it gives and the conclusion of the results
Use SFC on the command line. This will require administrator rights. To do this, you need to click the "Start" button and go to the "Standard" item. There is a "Command Prompt." You need to right-click on it and select "Run as administrator".
A black screen will appear in which the commands will be entered and the corresponding result will be displayed. The window looks like this:
You can enter one of the above commands in it, depending on the situation. For example, the first one you can use is SFC / scannow. What will it give? Firstly, the utility will check all the important system files, then compare them with the database from the cache.
If any inconsistencies are found, they will be repaired. During the operation of the utility, progress is displayed, after which 100% of the result of the procedure is displayed. There may be several:
- The program did not detect integrity violations. The conclusion of this proposal tells that everything is in order with the system;
- A reboot is required to complete system recovery . Restart the Windows system and run sfc again. The occurrence of this result when using SFC / scannow recovery may be due to a limited environment. The system proposed a solution to the problem.
This list of system responses occurs most often.
Other messages used less frequently
The program detected corrupted files, but cannot repair some of them. This is not the most favorable option, as the cache storing the whole and correct versions of the file may be damaged;
The utility cannot perform the requested operation. This result is displayed in case of any restriction on the part of the system. It is worth trying to reboot into safe mode and enter the commands here;
The utility detected corrupted files and successfully restored them. This message indicates that all system problems have been resolved. The result of running SFC / scannow in Windows 7 is saved at the path to the folder Windows \ Logs \ CBS \ CBS.log;
Conclusions and recommendations
Using SFC / scannow on Windows 7, 8, 10 can sometimes lead to unusual results. In the case when the utility says that it did not find any errors, and the system still works unstably, you need to restart SFC again. There are cases when the successful elimination of the problem was implemented from the third or even fifth attempt. The same goes for other unsuccessful results. It is also worth using the provided utility in safe mode, as individual services and processes will not interfere.
Conclusion
The article examined in detail the use of the SFC.exe / scannow utility. What it is and how to apply it has been described in the examples of various keys. To avoid using the SFC utility, it is better to monitor the system and prevent its destruction and malfunctions. This can be implemented using anti-virus software products, scanning systems and registry cleaning. It is also worth carefully monitoring what is installed on the computer. And the most important thing is to avoid downloading obscure files and programs from suspicious or unfamiliar resources. Compliance with the simplest rules of computer literacy eliminates the need to use the means of checking the integrity of the system and calling the wizard.