One of the things about Windows is sometimes it seems to do things in a way that doesn’t really make a great deal of sense. One of those situations is when an improper shutdown is detected or something like a USB stick is detached too quickly and Windows decides it needs to run a scan of the drive for errors, which in itself is not a problem. If you decide to skip, Windows will continue to ask you to scan because the dirty bit is still set on the drive. You let Chkdsk or Scandisk run and it will repair any problems with the file system and recover or repair any corrupted files affected because of it.
Although sometimes a CHK file cannot be recovered successfully because it has been too badly damaged, many of them can be used again, but you need to find out what type of file each one is and the correct extension needs to be applied. If Windows crashed while editing a document, there is only 1 CHK file and your document is missing, then renaming the file to mylostfile.doc could be worth a shot, but in most situations you won’t be so lucky or there’s a lot of files that need checking.Fortunately there are third party tools around that are able to help you recover CHK files by checking the headers of the files and identifying what the type of file is and what its original extension should be. Here’s a selection of ways to help you out.
1. UnCHK
Run the tool and it will ask you for the directory where the CHK files are and then a destination directory. The Scan Depth window gives various options about the recovery method; Whole Files will look at each file and check for a recognized signature, Embedded Files can pull objects like images from inside the CHK files and Floppy/Hard drive can check for cross linking in the files. The program was tested and worked fine on Windows 7.
Download UnCHK
2. FileCHK
Download FileCHK
3. CHK-Mate
One thing we noted about CHK-Mate was just how slow it was in trying to recover the files, over 20 minutes to scan 18 CHK files in Windows 7. It did look like it had crashed several times but did eventually finish, and at the end recovered 13, about the same as the other tools here. If the contents of a CHK file can not be identified, you have the option to extract all the readable text from the CHK file. This option is useful to recover information from a CHK file that is perhaps not intact enough to be recovered completely as a known file type.
Download CHK-Mate
4. TrIDNet
The tool itself is quite old dating back to 2004, but the database is still constantly updated meaning even the latest file types are recognized. Download the program and and unzip it, then download the definition files package and unrar the 1000’s of XML files into the TrIDNet main folder. Run the program and click on Rescan Defs to load them all in. Then browse for, or drag and drop a CHK file to identify it. The display will give a percentage of the likelihood a certain file extension matches the file. As an example, the screen shot shows TrIDNet thinks the scanned CHK file is an EXE rather than a DLL, and it is correct. The .NET Framework is required and the defs files and program are downloaded separately.
Download TRIDNet
5. FiletypeID
The program is fully portable and usage is broadly the same as TrIDNet where you browser for or drag and drop a CHK or any other file onto the window. Click the Analyse button and it will give you a list of types and possible extensions with the most likely being the highest percentage entry. A useful button is Details which can give more in depth information about certain types of file such as video and audio encoding/bitrates and archive compression etc. Works on Windows XP and above.
Download FiletypeID
6. Chk-Back
Although it does require installation, Chk-Back isn’t difficult to operate. Press the button to browse for the CHK files (usually in Folder.*** in the drive’s root) and it will show the files to be checked. Click Start and within a matter of seconds the process will be complete with a highlighted log file ready for you to save to a file if you wish or copy and paste elsewhere. A saved log file and the corrected CHK files will be created in a new folder called “ChkBack Results” in the same folder as the original CHK files. Works on Windows XP and above.
Download Chk-Back
7. The Manual way
Although obviously not the quickest or simplest method, one of the ways you can check and try to identify the CHK file is be by simply opening it with Notepad, Notepad++ or a Hex editor. All file types have a unique header in the first few bytes to tell one file apart from another, and although many will have unrecognizable characters at the beginning of the file, some contain a few characters at or near the start that can be recognized to help you identify what the file is. For example, “Rar!” at the start of a file is a WinRar archive, “ID3” means the file is an MP3 and “JFIF” in the first 10 bytes of the file means it’s a Jpeg image.
If you want to try and identify a file that has gibberish characters or something not easily recognizable at the beginning, a useful manual way is:
1. Open the file in a Hex editor such as HxD .
2. Highlight and copy the first 8 bytes or so of hex to the clipboard.