So what is a CHK file? Well, any time a program or Windows crashes, any files that were open are not closed properly. Part of closing is writing all the file location information in all the right places. Without this info, Windows can't find all the parts of the file. When SCANDISK or CHKDISK is run, all the parts are identified as "lost file fragments" and converted (if you want) into CHK files. Face it. Stuff crashes all the time. If you only run SCANDISK once a month, you get a month's worth of old crash junk. If you were working on (and lost) something important just before a crash, you might want to try to recover any data from any CHK files that exist. On the other hand, if you aren't in a state of panic over lost data, just delete any CHK files. A handy tip: Keep your disk defragmented. That way if you ever do lose it all, the lost file fragments will be more likely to be complete files.
Welcome Competition! A nice guy named Martin Kratz wrote a utility to compete with my UnCHK program. Amazingly, he sent me the source code. So... I compiled it and am offering it here for your consideration. Now you have two open-source CHK file recovery programs to choose from!
|Out-of-box supported file types||JPG PSP PSD GIF ZIP CAB EXE DLL OCX WRI BMP DOC PPT XLS PDF RTF HTM WAV MID AVI RAR TIF MP3 WPD FPX EPS CLP||3DS TIF EXE BMP SWF PSD AI GIF PST CAB RAR CHM MID PDF ZIP HLP MP3 DWG MPG LNK URL HTM JPG TTF MDB MOV QT DOC XLS RMI WAV AVI CDR TXT ASF|
|Can add more file types?||Yes, just drag a good file and drop it on the program (only applies if that file type has a standard header).||No.|
|Alters CHK files?||No. Makes a copy of the CHK file and gives the copy the correct extension.||Yes. Renames the original CHK file so it has the correct extension.|
|Recovers any CHK file?||Yes. Anything with a CHK file extension is checked. This makes things more flexible.||No. Only acts on files named like "FILE####.CHK". This makes things safer in case there are legitimate files with CHK extensions.|
|Identifies files by file header?||Yes. Also looks inside some files in an inexact way to try to
discriminate between different types of files that share the same
||Yes. Also reads inside the file in a more exact way to tell different files that use the same header apart.|
|Looks inside CHK files to recover cross-linked files?||Yes (if you choose the "hard disk" option).
|Looks inside CHK files to recover embedded
||Yes (if you choose the "embedded files"
|Runs fast?||Fast enough. And it has a percentage done indicator so you'll
know whether you have time for lunch.
||Yes. You won't believe it.|
|Has cool graphical interface?||Cool? Well... It has an interface.||No. No way. None at all. Except for the "Done" message when it finishes.|
|Stable?||It works for me.||Always. It's too simple to break.|
|Selectable directory?||Yes. You pick what directory CHK files are in and what directory you want recovered files to be in. The program itself can be anywhere.||No. Put the program in the same directory as your CHK files and run it.|
|False negative or false positive recoveries?||About a quarter the files it recovers are either mis-named duplicates (which can't be opened) or fragments (which you might not be able to open). But it allows you to choose scan depth options so you can decide how to trade off missed files and false detections.||Might not recover a file fragment and never recovers a cross-linked file, but the files it does recover can more likely be opened without errors.|
The UnCHK program link above (at the top of the comparison table) is for version 3. Version 3 was built for Windows 2000, but might work on computers as old as Windows 95. Version 2 was built for Windows 95, but might work on computers as new as NT4. Version 1 was built for Windows 3.1 and might work on computers as new as NT4. I recommend you use the newest version that applies, because the older versions really needed the fixes and features that are in later versions!