△ Recovering CHK files

I have an old One-Touch external hard drive from Maxtor. It went crazy and generated 10,000 FILE????.CHK files about a year ago. My wife and I were worried about that the entire hard drive has gone unstable so we simply gave up using it. Recently I found some spare time trying to search for some tools to recover those CHK files.

RecognizeImageFiles.py

One of the most important file types to recover is our photos. The first step I tried was to find some python script that can recognize image files by file content but not by file extensions. There is indeed such a nice little script imghdr.py in python repository. I modified it a little to have it specifically useful in CHK image file recovery (RecognizeImageFiles).

Screenshot of RecognizeImageFiles.py execution

It was quite successful and about 500 image files were recovered. But then, what about other types of files? I went online to search for third-party tools.

UnCHK and FileCHK

Surprisingly there isn't too many tools online. The most popular tools seem to be UnCHK (by Eric Phelps) and FileCHK (by Martin Kratz). They seem to be neat and useful. However, UnCHK (version UnCHK3) froze at the very beginning:



and FileCHK gave an error that reads:

Runtime error "9":
Subscript out of range

It's possible that they couldn't recognize my One-Touch in drive F. Whatever, they don't work in my case.

MediaHeal

I then found a MediaHeal from officerecovery. The description reads:

Recovers files from corrupted hard disks. Supported are all common file systems, including NTFS, FAT12, VFAT12, FAT16, and FAT32.

I downloaded the MediaHeal for Hard Drives and gave it a try. Unfortunately, this program only aims at the entire hard drives but doesn't allow users to check folder(s):

MediaHeal doesn't allow you to choose a folder (image shrunk to fit screen)

Much worse, it froze at the very beginning on this screen:

The excution of MediaHeal demo version froze at the very beginning (image shrunk to fit screen)

RecoverMyFiles

Finally, I found RecoverMyFiles from GetData. According to their website, this program allows users to recover deleted files even after the hard disk is reformatted (I didn't even know that it's possible):

Recover deleted files even if emptied from the Recycle Bin
Recover formatted hard drives, even if you have reinstalled Windows!
Recover your files after a hard disk crash
Get back files after a partitioning error
Recover documents, photos, video music and email.
Recover from hard drive, camera card, USB, Zip, floppy disk or other media

and it's able to recover 200 types of files. I downloaded the trial version and was amazed how efficient it was:

The screenshot of RecoverMyFile excution.

It ran smoothly and took less than 4 minutes to complete checking my 250GB One-Touch. You can check the content of each file to decide what file is valuable. Since this is a trial vresion so it doesn't allow real rescuing. But it already impressed me.

Other links

FILExt.com
http://filext.com/detaillist.php?extdetail=chk&Search=Search

Look for info about a file ext
http://shell.windows.com/fileassoc/0409/xml/redir.asp?Ext=jpg

A list of common file extensions
http://safari.oreilly.com/0596002491/winxpnut-APP-F

OfficeRecovery.com (data recovery software for corrupted files)
http://www.officerecovery.com/mediaheal/index.htm