I know this is not specifically a photography issue but since many of us with prosumer/professional-level DLSRs use Compact Flash cards, it is bound to happen to others as well.

I have a Sandisk 16GB Ultra card that occasionally had the camera reporting inability to access the card. I had to reinsert the card to continue using it. I was able to read the card and transfer the photo files to my computer drive. Today, the same thing happened again, just that nearing the capacity of the card, it failed one last time and the camera was subsequently unable to read it anymore. Despite reinsertion.

My other CF cards never once exhibited this problem, so it's pretty much isolated to this card.

The card is similarly unrecognisable on my computer CF card reader. I think the filesystem is toast, but I suspect the photo files are still intact. I would like to find ways where I can inspect the raw binary data in the card and hopefully recover the photos?

  • 1
    See also: photo.stackexchange.com/questions/1125/… Sep 16, 2010 at 18:29
  • I did see that question but I did not possess fundamental understanding about the differences between CF and SD card recording formats (not OS filesystem), and if raw card readers need to do anything special.
    – icelava
    Sep 17, 2010 at 13:48

8 Answers 8


There are two utilities from CGSecurity that might help.

  • TestDisk - Allows direct access to disk data and file recovery from corrupt partition tables.
  • PhotoRec - Specifically targeted at recovering photos by identifying byte patterns in images (& video) files.

Depending on what has caused your card to fail will depend on which of these tools will work best.

You can use TestDisk to do a raw backup of the card first to prevent further damage by using recovery tools incorrectly.

  • 2
    I used PhotoRec to recover my files thanks. Great that it's free, so guess cannot complain about the lack of a GUI.
    – icelava
    Sep 17, 2010 at 14:00
  • 2
    +1 for PhotoRec: My card had a destroyed file system (Windows and camera didn't recognise it), but I was able to recover all photos from it by using this great software. Can't recommend it more! Mar 29, 2011 at 9:48
  • 3
    +1 for recommending free and open source software that works. I tried to find the raw backup option in TestDisk but couldn't find it. I eventually just went ahead and copied the files on the card. It managed to recover every single photo. Excellent program.
    – Lilienthal
    Jul 29, 2012 at 9:04

Can you distinguish if it's the card that is inaccessible, or just it's filesystem? I know in Linux, you can access the raw device and try to get you data out of that (which should be possible, since it's usually just sequentially stored JPEG files).

On Windows and Mac, you can try recovery software recommended by SanDisk, demo version which shows you what it can rescue is avaiable here: http://www.lc-tech.com/software/rprodetail.html (see also SanDisk FAQ entry about that).

If you can't see the raw hardware then I guess your only chance is to try some data recovery service to tear the card apart and attempt to get you data from the flash chips.

  • The filesystem table itself somehow got corrupt. I have been testing out the various utilities and they can retrieve the data files.
    – icelava
    Sep 17, 2010 at 14:01
  • This software is more user-friendly than the open-source TestDisk, so i'd recommend for non-tech-saavy folks. Otherwise, TestDisk/Photorec can still get by with reasonable software experience.
    – icelava
    Sep 17, 2010 at 14:10
  • TestDisk/PHotoRec would not recognise a corrupt card despite it showing up on "My Computer" as a non-formatted drive. TestDisk did the job. Pricey but worth every cent if you have anything worth rescuing, and still way cheaper than cleanroom data recovery specialists. Jul 11, 2014 at 13:22
  • For a SD Card you do not need a cleanroom. Nov 3, 2021 at 2:11

If you are able to get to the card at all, you could try using Recuva from Piriform, Inc. It is a free download, and I have used it to get back files that were accidentally deleted.

One of the features listed is:

Recovery from damaged or formatted disks

Even if you've formatted a drive so that it looks blank, Recuva can still find your files on it.

  • Recuva appears to expect a known filesystem (i.e. FAT32, NTFS) before it can scan the card's drive. My card's filesystem is corrupt.
    – icelava
    Sep 16, 2010 at 15:53
  • @icelava - it may need to know what the filesystem was, but it shouldn't need a good filesystem on the drive to work.
    – Fake Name
    Aug 30, 2011 at 7:27
  • nope, Recuva couldn't do anything because there was no intact filesystem for it to even recognise.
    – icelava
    Aug 31, 2011 at 3:23

As Simon wrote, photorec is a good tool to recover lost data, not only image files. I the past I recover jpg files with success, but it used signatures to find the files, and I don't know if it has signatures for raw files.

Just a tip, first copy the content of the card with dd and the used photorec with the image created by dd. By making this one-time copy, you avoid making more damage to the card.

If photorec doesn't recognize raw files, see if you have any luck with other tools, as example: Foremost.

You also can read this article about recovering files from wiped disks.

  • Some of the disk-recovery tools like ddrescue actually work specifically by reading problematic sectors repeatedly. I don't know if this strategy is helpful with flash media, but honestly I wouldn't be too concerned about further damage to the card. Media is cheap enough that I follow a "one strike, you're out" policy — if a card has errors, I save what I can and then trash it.
    – mattdm
    Aug 30, 2011 at 4:52

I'm currently in the process of using ddrescue to recover photos from a corrupt CF card (I believe hardware failure).

The problem I have is not only parts of the filesystem/files being unreadable, but when I attempt to read a specific part of the CF card, the disk stops responding entirely, which makes it quite difficult to import files off it.

I imagine this might be a pretty special case, but in any case I've been able to piece most of the disk back together with ddrescue, using the -i option to skip the chunk where it fails, and otherwise read the sectors that work, to generate a new disk image file to use with PhotoRec.

If the CF card wasn't having such serious failures, I think it'd be possible with PhotoRec alone, as others have suggested.

ddrescue's main utility seems to be the way it lets you get as much of a disk as is available, and use various techniques (e.g. retries, which can be good on magnetic/optical disks) to fill in the gaps. You can keep re-running it to build up an image of the disk from whatever is readable with the various techniques. And it automatically works out how much it can actually read successfully between the failed/damaged sectors.


You can try using chkdsk first to recover partition. I am assuming your card is FAT32 formatted. You can use following command on Windows Command Prompt (cmd):

chkdsk g: /f /r /x

Please note that you should write your memory card drive name instead of g:

After chkdsk is completed and your drive is visible again, you should be able to recover your files.

If you cannot see your image files but can access to the memory card, you can use the software Recuva to rescue your image files.

  • 1
    I wouldn't feel comfortable using a writing operation like this on a medium before backing it up. Mar 13, 2014 at 22:25
  • Used chkdsk commands are not writing operations. As a logical choice it is of course would be a bad idea to use writing operations.
    – Tyathalae
    Mar 14, 2014 at 10:14
  • 1
    How can it fix errors without modifying the volume? Mar 14, 2014 at 10:21
  • It can fix partition table without touching the data. Also it can look for file signatures and fix them on MFT and File Allocation Table.
    – Tyathalae
    Mar 14, 2014 at 11:28
  • 1
    You cannot fix the MFT without modifying it. And modifying it risks breaking it even more. So I consider this a risky approach that shouldn't be done before creating a low level copy of the whole card. Mar 14, 2014 at 11:44

"The card is similarly unrecognisable on my computer CF card reader."

Basically for software to work, the card has to be detected in Windows Disk Management with correct capacity.

enter image description here

Verify with a different reader, if card still isn't recognized then in general this can't be recovered using software. If I am asked to handle a case like that I:

  • Open the 'case' and inspect the PCB using multimeter and microscope. If I can spot defects I'll try repairing them, and if successful I can now access the card. Some times it's enough to reflow the solder under the NAND chips. If a working and matching donor board is available, often NAND chips can be transferred to donor PCB.

  • If unable to repair I unsolder NAND chips and 'dump' them using a reader. Using specialized software I then convert the dump to a logical file system using software that emulates the controller (or tries as good as it can) from which files can be recovered. Ideally result is a coherent file system, however sometimes raw recovery is highest achievable. It's the logical image reconstruction part that is most complex and time consuming.

NAND readers are not overly expensive (but still too for a single case probably), it's the software that is needed to convert the raw dump to a logical image that is. I use the Soft Center reader and software (called Flash Extractor).

With regards to logical photo recovery software, often mentioned names are PhotoRec and Recuva, also free and very good is R-Photo made by the company that produces R-Studio which is used in many labs for logical data recovery.

If card (whatever card, CF, SD etc.) is detected but physical capacity is incorrect:

In these cases dumping the NAND is almost always required. Typically physical capacity is decreased to MBs rather than GBs. It's an indication controller is working but in let's call it a safe mode. It is either unable to detect the NAND memory -or- NAND translation table is corrupt. See this translation table as a 'FAT' for the firmware, only this table is used by firmware to map LBA addresses to actual NAND pages.


I had an SD card go bad during a vacation to Disney World. The camera said the card was unreadable. And the computer said the card was blank. When I knew I had 100+ pictures on there. And this was before I got back to the hotel to back them up.

So I remembered this un-erase program called "Recuva" (Windows only) that scans a volume (hard drive, flash, etc) looking for deleted files.

Sure enough, it found every single one of them and I was able to restore them all. Best of all, the program is free.

So Google "Recuva" and try it.

  • 1
    Duplicate answer. I did try recuva before but it expected a known filesystem to be present on the card. My card was toasted until the filesystem was unrecognisable.
    – icelava
    Mar 29, 2011 at 4:46

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