How to open a CHK file? Recovering data from chk files

The other day they brought me a flash drive, on which one of the folders suddenly disappeared. All that was left of it was a shortcut that didn’t open anything. Only the folder FOUND.000 was found, and there were the files file0001.chk, file0002.chk... many files. The folder is hidden.

If you use an alternative file manager, for example, Total Commander, you will probably see it right away. In standard Explorer, you need to use any open folder in the menu, select "Tools - Folder Options - View" find and check the box next to "Show hidden folders and files."

So, the folder was found. In general, it is the result of the ScanDisk program. Windows runs it when it “thinks” that integrity may have been compromised file system, for example, if the computer is turned off incorrectly, the file system malfunctions, or for some other reason.

If you are interested, it is not difficult to find information about why these unfortunate chk files appear. Now we need to understand what to do with them. In general, chk files contain information located in orphaned areas of the disk. Speaking in simple language- Some of the lost data may be there. And they can be restored accordingly.

A little more theory. A file signature is a constant, a certain permanent set of characters that allows you to uniquely identify what type of data is contained in this file. To put it simply, this is a piece of code in a file, from which you can clearly understand what kind of file it is, what program it was created by, and other information. For example, an exe file always begins with the characters “MZ”, a Rar archive has “Rar!” in its code. etc. Accordingly, by looking at the file and studying its signature, you can understand what data it contains. After that, just open it with the appropriate program and, making sure that everything is correct, change the extension to the correct one.

It’s just impossible to remember all the signatures (for example, the file signature png format looks like this “0x89504E470D0A1A0A”), and manually viewing several hundred or even thousands of files is almost impossible.

And here 2 programs will come to the rescue, which will restore many things automatically.

The first of them is written by Sergei Bocharov. Using it, I was able to recover most of the data from a flash drive. Of course, the file names remain like file0001, file0002, and each of them will have to be looked through and renamed. But at least now these files were organized into folders and already had the correct extension.

The second program by Mikhail Mavritsin behaves more strangely, although it potentially has greater capabilities. In general, its functions are absolutely similar to ChkRepair, but the set of signatures is different. And in my case, ChkRepair had more. On the other hand, a clear advantage of CHKParser32 is the ease of expanding the list of signatures. To do this, you just need to add a line to the ini file that comes with the program. And its strangeness is that for some reason it renames unrecognized .chk to its own format.

And if, after all, the programs were unable to recognize some chk files, I recommend looking at them manually rather than deleting them, in case you find something interesting! 🙂 As a result, I was not able to recover everything, but 80% were saved. 😉

You are here because you have a file that has a file extension ending in .chk. Files with the .chk extension can only be launched by certain programs. It is possible that .chk files are data files and not documents or media, which means they are not intended to be viewed by anyone.

what is a .chk file?

Fragments of a file created by the associated OS Microsoft Windows also called stored file fragments and are generally classified as data files. These files are attached with the .chk extension and contain data associated with a file that has been deleted or stored elsewhere on the disk. The ScanDisk application, also called CHKDISK, is an applet built into most Microsoft versions Windows, OS. This applet is used to find and delete unused files created on the system and can find CHK files to permanently delete them, since files that match the contents of these CHK files have already been deleted or moved by users to another directory. CHK files are typically located in the system directory labeled "Found" and these CHK files are also created after using the ScanDisk applet to scan storage devices connected to the computer. Eat third party applications, designed to open and view the contents of these CHK and software CHK-Mate is an example program that can be installed in Microsoft system Windows to implement support for this purpose. The FileCHK program and the UnCHK software were, on the other hand, designed to provide users with functionality to recover or restore the data contained in the CHK file.

how to open .chk file?

Run the .chk file or any other file on your computer by double-clicking it. If your file associations are configured correctly, the application that is intended to open your .chk file will open it. You may need to download or purchase correct application. It is also possible that you have the correct application on your computer, but the .chk files are not yet associated with it. In this case, when you try to open a .chk file, you can tell Windows which application is correct for this file. From then on, opening the .chk file will open the correct application.

applications that open .chk file

MS Windows OS

DIY DataRecovery CHK-Mate

DIY DataRecovery CHK-Mate

a word of warning

Be careful not to rename the extension on .chk files or any other files. This will not change the file type. Only special program To convert, you can change the file from one file type to another.

what is the file extension?

A file extension is the set of three or four characters at the end of a file name, in this case,  .chk. File extensions tell you what type of file it is, and tell Windows what programs it can open. Windows often associates a default program for each file extension, so that when you double-click a file, the program launches automatically. Even though a program is no longer on your computer, you may sometimes receive an error message when you try to open the file in question.

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On storage devices - flash drives or hard drives, you can find a hidden folder FOUND.000, which, as a rule, contains files of the FILE0000.CHK type. But few people know what these files are, what they are needed for and whether such a folder can be deleted.

Note that the FOUND.000 folder is hidden. If you don't see it, it doesn't mean it doesn't exist.
Digression: To view hidden files and folders, click in any active window(for example, “Explorer” ALT button on the keyboard. At the top, select the menu Tools-Folder Options-View. Find the item “Show hidden files, folders and drives.”

Where does the FOUND.000 folder come from?

The FOUND.000 folder is created by the built-in disk scan tool CHKDSK when you run a scan manually or during automatic system maintenance in the event that the disk has file system corruption.

The files with the .CHK extension contained in the FOUND.000 folder are fragments of damaged data on the disk that have been corrected: i.e. CHKDSK does not delete them, but saves them in the specified folder when correcting errors.
For example, you were copying some file, but suddenly the power went out. When checking a disk, CHKDSK will detect damage to the file system, fix it, and place a fragment of the file as a file FILE0000.CHK in the FOUND.000 folder on the disk to which it was copied.

That is, the file usually contains a fragment of the file, and not a full file.
Is it possible to recover the contents of CHK files in the FOUND.000 folder
As a rule, data recovery from the FOUND.000 folder fails and you can simply delete it. However, in some cases, a recovery attempt may be successful (it all depends on the reasons that caused the problem and the appearance of these files there).

How to recover data from a .CHK file?

There are a sufficient number of programs for these purposes, for example UnCHK and FileCHK (these two programs are available at http://www.ericphelps.com/uncheck/). If they did not help, then most likely it will not be possible to restore any of the .CHK files.
Some notice CHK files in the FOUND.000 folder in file manager on Android and are wondering how to open them (because they are not hidden there). Answer: nothing (except for the HEX editor) - the files were created on the memory card when it was connected in Windows and you can simply ignore it.

Sometimes you get up in the morning, turn on the computer, everything goes as usual... And suddenly ScanDisk starts up. We wait until it finishes working, load to the end and see that the parts important files no:(If we haven’t seen any new folders on our disks, don’t despair, go to “My Computer – Tools – Folder Options – View” and look for and check the box next to “Show hidden folders and files.” Yes, to save additional protection OS, do not forget to return this property to initial state. Then we look again at the contents of our disks and what do we see? Some strange folders FOUND.000, FOUND.001, etc. appeared, and in them the files file0001.chk, file0002.chk... What happened?

When, if the computer is turned off incorrectly, the file system malfunctions, or for some other reason Windows reasons“thinks” that the integrity of the file system may have been compromised, it launches ScanDisk. This program differs from data recovery software in that when errors are detected in the file system, it simply corrects them, and stuffs the data that it doesn’t know where to put into chk files. In the process of such work, “traces” are destroyed that could be used for direct data recovery. Thus, it turns out that after ScanDisk has gone through the partition, the probability of successfully using special software (for example) tends to zero, all that remains is to tinker with the .chk files in the hope of recovering data from there. So…

The ScanDisk utility has many parameters: scandisk.exe |/all] | /custom]

Actually, the purpose of this article is not to study the ScanDisk parameters, so I will not consider them all, but will only show in which case we will receive our treasured chk files and what to do with them subsequently. The command c:\> scandisk.exe will check the integrity of the file system on the current drive c:\ and allow you to correct any errors found.

When you specify the /autofix option, detected errors are fixed automatically without first asking for permission. The /nosave parameter allows the ScanDisk utility to delete information located in orphaned areas (clusters) of the disk. If the /nosave option is not specified, information from orphaned areas is saved in the root directories of the corresponding drives in the files FILEnnnn.chk, where "nnnn" is serial number file. As a result, files such as file0001.chk, file0002.chk, etc. appear on the disk.

Windows default calls Scandisk with the /autofix parameter, which is why we get these files, which contain information located in lost areas (clusters) of the disk.

I think it’s now clear why these unfortunate chk files appear. We'll figure out what to do with them. As already mentioned, chk files contain information located in orphaned areas of the disk. In simple terms, there may be some data there that you did not find after downloading. How to perform data recovery? How to get an irretrievably lost collection of papier-mâché photographs of toy Pokemon or a collection of “Thief Taiwanese Chanson” that has been collected over the years? :)

So, we have folders with the files file0001.chk, file0002.chk, etc. For further actions for now we only need text editor and certain knowledge. Let's start with a definition. A file signature is a constant, a constant set of characters that allows you to uniquely identify what type of data is contained in a given file. Again, to put it simply, this is a piece of code in a file, from which you can clearly understand what kind of file it is, what program it was created by, and other information.

For example, an exe file always begins with the characters “MZ”, a Rar archive has “Rar!” in its code. etc. Do you see what I'm getting at? That's right, by looking at the file and studying its signature, you can understand what kind of file it is. Again, it is impossible to remember all the signatures, because not everything is as simple as it seems at first glance (for example, the signature of a png file looks like this “0x89504E470D0A1A0A” and remembering it is clearly problematic, unless you are Johnny Mnemonic, of course!). True, a signature is not the only means.

Manual sorting

Let's now move directly to practice. We take the first chk file we come across, open it through a text editor and look at its contents. Except for something like “sek%E ‘Ґcrm-Ъ7€‡P 9 NУёыѓЋ)y=3” you won’t often see it throughout the entire file, so a quick inspection will rarely give us anything. First of all, we try to see familiar signatures. Did you see something familiar? Great! We close the editor, replace the file extension from chk with the one we recognize and rejoice at the result, jump on the spot, clap our hands! :)

If you're lucky, the file will open correctly with the appropriate program. But this is the simplest and most successful case. Now let's go back a little. We did not find a familiar signature. What to do next? Then we begin methodically, manually reviewing the contents of the file and trying to draw from there useful information. What do I mean by useful? Well, for example, if we found pieces of text, then there is a high probability that it Word file or Excel, if something like “KONICA MINOLTA DIGITAL CAMERA”, then, obviously, these are your photos or videos from the same camera with mov extension(most common in at the moment, although many already write directly to avi) and so on.

Having in hand this information we can sort all chk files by types we know. It also makes sense to pay attention to the size of chk files. If the file takes up about 680-740 megabytes, then most likely it is a movie and you can simply select required extension(avi, mpeg, etc.). I can already see the smile spreading across your face with pleasure and the feeling that you will easily return all the files, but, unfortunately, this is not the case. Very often, chk files may not contain all, but only part of the data in the source file. For example, after changing the extension of a chk file, we get a broken doc or a piece of a picture. In these cases, to obtain satisfactory results, it may be necessary to use specialized programs, designed to recover data from damaged files of specific types.

The topic of using such software is quite extensive and is beyond the scope of this article. If necessary, information about programs that perform data recovery from broken files specific type can be found using search engines. Also, .chk files may simply contain “garbage” that you don’t need.

Automatic sorting

That’s basically it, we identified one whole chk file and returned it to its place. But this is only one file, and there can be about a thousand or more of them... So, should you view all the files manually? Right! Of course not... :) We thank Mikhail Mavritsin, who wrote, from my point of view, the most sensible of free programs for automatic sorting.chk. So, welcome to our assistant -.

After launching the program, we are presented with the window shown above. As you can see, everything is functionally quite convenient, you can see the number of known signatures, the number of chk files in the scanned directory and, at the end of the process, the number of recognized ones. During testing, all the files that I tried to “feed” to the program were successfully “swallowed” and recognized. The program works very quickly. Another advantage is the ease of expanding the list of signatures. To do this, you just need to add a line to the ini file that comes with the program.

For example, during testing, within 5 minutes I studied the signatures of files like mov and already next stage testing, the program easily found and recognized them. If you want to study the work of the program in more detail, then you are welcome to contact her. As you can see, by spending 2 minutes working with the program, we save a lot of time that we would have spent on manual sorting. However, I do not recommend forgetting about it. If, after all, the program was unable to recognize some chk files, I recommend looking at them manually rather than deleting them, in case you find something interesting! :)

Andrey Zelnikov, especially for the site.

Reproduction or quotation is permitted provided that a link of the form is indicated R.LAB data recovery to the original source.

Sometimes you get up in the morning, turn on the computer, everything goes as usual... And suddenly ScanDisk starts up. We wait until it finishes, we boot to the end and see that some of the important files are missing: (If we don’t see any new folders on our disks, don’t despair, go to “My Computer – Tools – Folder Options – View” and look for and install check the box next to “Show hidden folders and files.” Yes, to preserve additional OS protection, do not forget to return this property to its original state after completing all manipulations. Then we look again at the contents of our disks and what do we see? Some strange folders have appeared? FOUND.000, FOUND.001, etc., and in them the files file0001.chk, file0002.chk... What happened?

When, due to an incorrect shutdown of the computer, a file system failure, or for some other reason, Windows “thinks” that the integrity of the file system may have been compromised, it launches ScanDisk. This program differs from data recovery software in that when errors are detected in the file system, it simply corrects them, and stuffs the data that it doesn’t know where to put into chk files. In the process of such work, “traces” are destroyed that could be used for direct data recovery. Thus, it turns out that if, after data loss, a ScanDisk was passed on the partition, the probability of successful recovery special software(R-Studio, for example) tends to zero, all that remains is to tinker with .chk files in the hope of recovering data from there. So…

The ScanDisk utility has many parameters: scandisk.exe |/all] | /custom]

Actually, the purpose of this article is not to study the ScanDisk parameters, so I will not consider them all, but will only show in which case we will receive our treasured chk files and what to do with them subsequently. The command c:> scandisk.exe will check the integrity of the file system on the current drive c: and allow you to correct any errors found. When you specify the /autofix option, detected errors are fixed automatically without first asking for permission. The /nosave parameter allows the ScanDisk utility to delete information located in orphaned areas (clusters) of the disk. If the /nosave parameter is not specified, information from the orphaned areas is saved in the root directories of the corresponding disks in the FILEnnnn.chk files, where "nnnn" is the file serial number. As a result, files such as file0001.chk, file0002.chk, etc. appear on the disk. By default, Windows calls Scandisk with the /autofix parameter, which is why we get these files, which contain information located in lost areas (clusters) of the disk.

I think it’s now clear why these unfortunate chk files appear. We'll figure out what to do with them. As already mentioned, chk files contain information located in orphaned areas of the disk. In simple terms, there may be some data there that you did not find after downloading. How to perform data recovery? How to get an irretrievably lost collection of papier-mâché photographs of toy Pokemon or a collection of “Thief Taiwanese Chanson” that has been collected over the years? :)

So, we have folders with the files file0001.chk, file0002.chk, etc. For further actions, for now we only need a text editor and certain knowledge. Let's start with a definition. A file signature is a constant, a constant set of characters that allows you to uniquely identify what type of data is contained in a given file. Again, to put it simply, this is a piece of code in a file, from which you can clearly understand what kind of file it is, what program it was created by, and other information. For example, an exe file always begins with the characters “MZ”, a Rar archive has “Rar!” in its code. etc. Do you see what I'm getting at? That's right, by looking at the file and studying its signature, you can understand what kind of file it is. Again, it is impossible to remember all the signatures, because not everything is as simple as it seems at first glance (for example, the signature of a png file looks like this “0x89504E470D0A1A0A” and remembering it is clearly problematic, unless you are Johnny Mnemonic, of course!). True, a signature is not the only means.

Let's now move directly to practice. We take the first chk file we come across, open it through a text editor and look at its contents. Except for something like “sek%E ‘Ґcrm-Ъ7€‡P 9 NУёыѓЋ)y=3” you won’t often see it throughout the entire file, so a quick inspection will rarely give us anything. First of all, we try to see familiar signatures. Did you see something familiar? Great! We close the editor, replace the file extension from chk with the one we recognize and rejoice at the result, jump on the spot, clap our hands! :) If you're lucky, the file will be opened correctly by the appropriate program. But this is the simplest and most successful case. Now let's go back a little. We did not find a familiar signature. What to do next? Then we begin to methodically, manually review the contents of the file and try to glean useful information from there. What do I mean by useful? Well, for example, if we found pieces of text, then there is a high probability that it is a Word or Excel file, if something like “KONICA MINOLTA DIGITAL CAMERA”, then, obviously, these are your photographs or videos from the same camera with the mov extension ( the most common at the moment, although many already write directly to avi) and so on. Having this information in hand, we can sort all chk files by types known to us. It also makes sense to pay attention to the size of chk files. If the file takes up about 680-740 megabytes, then most likely it is a movie and you can simply select the desired extension (avi, mpeg, etc.). I can already see the smile spreading across your face with pleasure and the feeling that you will easily return all the files, but, unfortunately, this is not the case. Very often, chk files may not contain all, but only part of the data in the source file. For example, after changing the extension of a chk file, we get a broken doc or a piece of a picture. In these cases, to obtain satisfactory results, you may need to use specialized programs designed to recover data from damaged files of specific types. The topic of using such software is quite extensive and is beyond the scope of this article. If necessary, information about programs that perform data recovery from damaged files of a specific type can be found using search engines. Also, .chk files may simply contain “garbage” that you don’t need.

That’s basically it, we identified one whole chk file and returned it to its place. But this is only one file, and there can be about a thousand or more of them... So, should you view all the files manually? Right! Of course not... :) We thank Mikhail Mavritsin, who wrote, from my point of view, the most intelligent of the free programs for automatic sorting.chk. So, welcome to our assistant – CHKParser32.