Just discovered I have gotten a FOUND.000 folder on my usb drive. I guess from running chkdsk once. It has three files in it:

  • FILE0000.CHK
  • FILE0001.CHK
  • FILE0002.CHK

What exactly can I do with these files? What are my options? Are they lost files? Are they garbage? Can I use them for anything at all? Or will I just have to delete them?

  • I think you should switch and accept NGLM's answer, he actually tells you what you can do with them.
    – barlop
    Nov 21, 2012 at 0:00

8 Answers 8


Those are recovered lost cluster chains. The clusters might get lost when file operations are interrupted abnormally. In the case of an USB flash drive, that might happen when you physically unplug the device before "Safely Removing Hardware" (actually, before the OS has finished writing cached data to the medium).

A single .CHK file may contain

  • a single entire file (or multiple entire files),
  • a part (or multiple parts) of a file (or multiple files) or
  • a really messy mix of the above.

Most often recovering something useful from those .CHK files is an extremely complicated (though, not entirely impossible) thing to do, thus, most often, it is just less of a headache simply to delete them and forget what happened.*

* This is not the case, when you realize, that you're missing something important. In this case it might turn out to be worth spending some effort to recover the lost data.

  • You can always open them in a hex editor and look at them. If you can tell what they are (like a text document you were typing up), then you don't need to go through the trouble of worrying if something is lost.
    – Cole Tobin
    Apr 11, 2014 at 0:29

Wow, nobody has pointed this out yet.. unless I missed it.

You can rename them, if you have some idea of what they are. And then they can just open.

so, if you had some excel files on a floppy disk, as a friend did once, or could be a usb key to be up to date! and you had some file corruption issue and scandisk(chkdsk nowadays!) was run on it, and those CHK files produced, then you can try renaming them from CHK to XLS and may open them. I guess if it's on removable media as it is in your case, then you may have more of a clue what type of file it is.

I have renamed them on 2 different occasions, saved 2 different people!

makes me think, maybe linux's file command would identify what they are in some cases. or TRID file identifier. worth a try.

he says a number of things, well worth reading the link, and he mentions these for identifying the files.

UnCHK by Eric Phelps
FileCHK by Martin Kratz

  • also, maybe quickview or quickview plus
    – barlop
    Sep 15, 2015 at 22:36
  • Renaming them did not work for me, so I used the Ramond.cc link here in this solution and ran UnChk which converted the CHK files like a charm! Thanks for the link, barlop.
    – bgmCoder
    Oct 23, 2017 at 16:10

If there are important files missing: recover them!

There are nice utilities available as barlop already pointed out.

But another way is to restore them yourself. To make this a little comfortable, let explorer show the file extensions and let the preview pane show the files as text files. Then you really can make a good guess on which file extension the chunk files need to get, rename the extension and the preview pane shows the document in its native format, if succeeded (i.e. your made the correct guess).

To show the .CHK files as text files, use the registry editor to add or search for the .chk key under HKEY_CLASSES_ROOT. Add two string values (REG_SZ), e.g. like explained here:

  • Content Type = text/plain
  • PerceivedType = text

Now, what files should get what extension. Some tips:

  • PDF: The string PDF should be found at the first (short) line,
  • PNG: The string PNG should be fount within the first two lines,
  • ZIP: The first line starts with PK (but note that there are other formats starting with PK),
  • DWG: AutoCAD drawings start with AC####, where #### is the version number of AutoCAD drawing file format,
  • SVN: If the first line starts with DELTA, then there is a good possibility that it's a SubVersion revision delta file which has no extension,
  • GIF: The first line starts with GIF,
  • etc...
  • Nautilus in Ubuntu 12.04 generates previews for .CHK files containing JPG and AVI content
    – tommyk
    Dec 14, 2012 at 20:16

They are file fragments "recovered" from running a disk check in Windows.

If you know you are not missing any files, you can just delete them. I have never had a genuine case where they are real data.

  • 2
    I'm not sure those are always whole recovered files. They might be just parts of files.
    – geek
    Mar 27, 2010 at 10:21
  • 1
    Could it be that those only ever appear on FAT volumes? I can't remember chkdsk creating them on an NTFS volume.
    – Joey
    Mar 27, 2010 at 11:45
  • @Johannes: I think files with that particular name format are FAT; but NTFS does create files like that, from time to time - I've seen them on my system, with a slightly different name format. NTFS is more reliable than FAT and doesn't (as often?) end up with cross-linked clusters which are the chief cause of these in FAT. Mar 28, 2010 at 18:01
  • " I have never had a genuine case where they are real data." <-- I have seen 2 genuine cases. people had those files, and in both cases I renamed them from chk , (to xls maybe - excel) and saved their ass.
    – barlop
    Nov 20, 2012 at 23:57

No!! dont delete that!! they contain files that were present in your drive, may be useful and are lost accidently, most probably when you remove the drive quickly!! There is a command line converter for these files which may be found free over the net!! The name's "FileCHK" and I once recovered many files using this method!!


I just successfully saved a ton of irreplaceable files by retrieving them from the file.000 directory. I was denied access at first and had to change the permissions following some advice from this post. After changing the permissions, I was able to copy and retrieve the files without using any additional data recovery/chk software.

The first answer didn't work for me, but the solution from AdamGoff worked perfectly.

Backstory: one of my folders suddenly disappeared my from my external drive due to some drive error. I ran dskchk and then went on to try some data recovery software (easeus & virtuallab) but after almost a days worth of scanning they didn't recover/reveal the files in the file.000 directory.

I finally found that my files still existed in file.000 with active@-file recovery software, but I have a 10 year old version and their file recovery is painstakingly tedious when dealing with the amount of subfolder structure and files I have. So I ended up using the permissions changing to access the files directly from explorer to retrieve my precious files. So if anyone else encounters a similar problem. Check your drive's file.000 folder (may be hidden).

  • -1 "AdamGoff" doesn't exist anywhere on this page
    – barlop
    Jul 30, 2016 at 16:03

The Achilles' heel of all USB-driven external hard drives is that they push your laptop's power capabilities to the limit: even slight brownouts become extremely likely, making data corruption inevitable, and Microsoft complicates matters further by assuming it should run chkdsk for you whenever it likes -- even when low power conditions guarantee both a chkdsk fail and the corruption of the very data the utility is trying to 'save' for you. Not sure why the real world and the Microsoft world have diverged so much here.

  • 1
    which OS does chkdsk keep running on usb drives with? usb sticks don't use much power do they? and external hard drives get powered externally. How do you know they use a lot of laptop power? how are you measuring it?
    – barlop
    Dec 28, 2010 at 12:40

I recently used Chk-back to recover the .chk files that chkdsk creates, better still it is free and supports a large number of popular file types.

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