I'll leave it up to you to decide if this is sufficiently on-topic. It does relate to SD cards used in photography specifically.

My Nikon D7000 does something funny to my SD cards and I can't figure out what is going on. The cards have been working fine and still work fine in the camera (photos gets recorded, no issues), but 2 of my cards have now stopped working in my PC. The computer doesn't see a card being present at all.

I've worked around the problem so far by taking an unaffected card and copying the images across using my camera (the D7000 has two SD card slots), but I'm quite uncomfortable with cards failing like this. Does anyone have similar experiences? What is causing this and how can I restore the cards?

  • \$\begingroup\$ Please indicate how you read the cards into your computer. \$\endgroup\$
    – Itai
    Apr 1, 2012 at 2:18
  • \$\begingroup\$ @Itai, I use a cheap USB SD card reader, one of those you sometimes get bundled with a card. \$\endgroup\$
    – SoftMemes
    Apr 2, 2012 at 12:16
  • \$\begingroup\$ I have that same problem. Except with me, my cards only work in certain computers \$\endgroup\$
    – J. Walker
    Apr 2, 2012 at 19:23
  • \$\begingroup\$ can you view the photos, new and old, in the camera? \$\endgroup\$
    – Skaperen
    Jul 22, 2015 at 12:22

3 Answers 3


Regarding the function of the sdcard/s in question: If a card is reading and writing without issue inside your camera, that’s a good sign that card is functioning properly. However, you can try the following:

  1. After backing up the data on the sdcard, format it with your camera.
  2. Insert the card into your reader and check if your PC 'sees the card.’
  3. If the card does not show up, try having a friend (with a working reader) format the card on their computer and try again.

Skip to the end of this answer for an explanation of this process.

As far as USB card readers go, they can malfunction for a variety of reasons that may or may-not be related to the reader itself. Here are a few steps for troubleshooting the reader:

  • If the card reader is connected to a USB hub, try connecting it directly to your computer.
  • If the reader is already directly-connected, try using a different port*.
  • If the reader has a detachable USB cable, try swapping it out for another.
  • Lastly, try using the reader on another computer.

If all these steps fail, it may be time to pickup a new card reader.

(*USB ports often come in pairs, if possible, connect to another port as far away from the one you’ve been using as possible.)

Formatting the card (which is different from deleting all images or 'clearing' it) is a process that prepares the card to store files, by establishing a file system. Removable media, like sdcards or USB flash/thumb drives, occasionally end up with errors in the file system on the card. The most common cause of such errors, is a card being 'removed' (unmounted) incorrectly e.g., a card is taken out of the reader, while the computer is still accessing it.

It is possible for your sdcard to function inside the camera, but to be unreadable on your PC, when such file system errors occur. (Re)Formatting the card will effectively erase all data on the card and will re-create the necessary file system.


There could be quite a few problems that would cause SD cards not to be read by a computer:

  • Check the metal leads of the card and wipe it off with a clean surface. There may be some sort of oil that could be preventing your computer from reading the card.

  • The problem may also be with your SD card reader on the computer. Try using a different card and see if any thing happens.

There should be no reason to worry about the cards if they continue to work on the camera, but if you can't get these solutions to work, use a different card.


I had this problem with my older (T1i) Canon camera: It wouldn't always work with some SD cards. Fixed it thus: dipped the connector end of an SD card in Vaseline (only as deep as the contacts). Then wiped the Vaseline off with toilet paper. Inserted the card a few times into the camera. No more problem.

Theory: Corrosion on the camera contacts. Sliding a chip in several times knocked the corrosion off, and the residual Vaseline prevented the problem from coming back. YMMV, but I think this is unlikely to do harm. I did this instead of replacing the camera since it's hard to get "unreliable" problems fixed.


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