It started, bizarrely, with my CANON 650D freezing for a while. I tried turning it off and it wouldn't - I suspect I did this too soon after taking a photo and the card was still saving the data.

Now when I try using my camera it flashes a message saying there's something wrong with the SD card (which is 16gb). I've tried formatting it to the camera, but it was unable to.


  • 7
    What does it say is wrong? What is the exact error message?
    – mattdm
    Apr 21, 2013 at 12:05

4 Answers 4


From the description you've given, especially the part about the camera failing to format the card, it sounds like there's just simply something wrong with your SD card, so that probably means throw it out and buy a new one. They aren't that expensive these days.

Even if you can get the card to work again, it's not worth continuing to use a card that you already suspect has problems.

It's a fact of life that some SD cards fail at random times, and sometimes this means they'll fail when they're quite new. Count yourself lucky that you haven't lost a bunch of irreplaceable photographs that were on it.

Before you throw it in the trash, however, a few simple troubleshooting steps:

  • Try another SD card in the same device. Same problem? Then it's probably the device, not the card.

  • Try the problem SD card in a different device. Any problems? Then it's probably the card.

  • Check for dust/dirt/fluff in the SD card slot of the device (camera) and on the SD card's contacts (avoid cleaning them unnecessarily especially with dry fabric, as static electricity is harmful to them).

  • 2
    Or, since the card is apparently new, exchange it for another one.
    – Caleb
    Dec 27, 2015 at 18:15

Try fully erasing your card on the computer:

  • If you use Windows: Download the official SD Formatter, enable overwriting from the Options button and proceed to format the card.

  • If you use Mac OS X or most Unix variants: erase the card by running the following command with superuser privileges: dd if=/dev/zero of=/dev/{whole disk device identifier}. After it finishes, reporting an amount of input blocks/output blocks/average speed, remove the card and attempt to reformat it in-camera.

Both methods are destructive to any existing contents and will take quite a lot of time.


If it's brand new I would just save the time and go back to the shop and complain.

If you purchased it on ebay you may want to check: http://sosfakeflash.wordpress.com/2008/09/02/h2testw-14-gold-standard-in-detecting-usb-counterfeit-drives/

Sometimes, some Ebay SD card sellers sell a "16gb card" that actually only has maybe, 32mb", or some other small amount.

Basically, it writes data to the card to fill it, and reads it back. If something is missing the dodgy it is.

I've been stung by ebay cards before. I dare not trust them no more.

  • I used to have a few allegedly class 10 cards that are slower than mid-high end class 6 Lexar bundled with my camera, for that matter…
    – Ryccardo
    Apr 21, 2013 at 15:10
  • I've bought ebay cards that were perfectly fine, too. Be aware as with anything. In general, electronics retail stores charge about 150% markup on SD cards. You can usually get them for around half as much from computer parts retailers. I favour Sandisk (Ultra, Extreme or better, not "Blue"). Apr 22, 2013 at 6:58

Make sure the SD card isn't locked - making it a read-only SD card. I've tripped the SD card write lock putting them into my D7000 a few times.

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