Corrupted SD Cards

Corrupted SD Card⇐ Has this ever happened to you? You’re importing images into Lightroom or Photoshop and one or more of your images has multicolored streaks or part of the image is missing altogether. The images look fine on the camera’s LCD, but in your software, at least some of the images are a mess. Panic ensues.

What happened? Your card has gotten corrupted, and before I go any further, the answer is, “no, the corrupted images probably cannot be salvaged.” There is a program called “Zero Assumption Recovery;” however, it does not appear to be compatible with recent camera file formats. You can still try it. Likewise, CHKDSK may be able to recover your work. Again, you’ve got nothing to lose by trying it. (Disclaimer: I have not tried either of these techniques. Try at your own risk.)

There are several possible causes. Turning off the camera while it’s writing images, a malfunctioning card reader, improperly or incompletely formatted cards, or a failing card can cause this to happen. However, the most common reason appears to be a faulty or failing card reader. It happened to me and I never was able to figure out how, but I trashed the SD card, took a few precautions, and it hasn’t happened since. Quality SD cards are robust and should last years; however, stuff happens. I’ve read of photographers who have accidentally run an SD card through the laundry and were still able to download images. In contrast, CF cards are a bit more fragile.

The reason the image may look fine in your camera is because it is displaying an embedded, low-quality JPG file, not the entirety of the image file itself. Unfortunately, this means that the card can be failing and you have no idea until it’s too late. How do you prevent this?

  1. Use top quality SD cards from Lexar, SanDisk, etc. I’m always surprised at people who spend $1,000 or more on a camera and then put cheap cards (or batteries, but that’s another story) in them. The pleasure of saving a few dollars will evaporate if you lose images.
  2. Format the card in your camera before each use. Formatting resets the file pointers on the card, essentially refreshing the file structure. It takes about 15 seconds, tops.
  3. Use a quality SD card reader when importing/transferring images. Again, SanDisk and Lexar make high-quality card readers.
  4. Use the card reader built into your laptop/PC if it has one. The more direct the connection between the card and your computer, the less likely you’ll run into problems.
  5. For the same reason, it’s probably best not to use a USB hub with your reader.
  6. If you can’t import/copy from one USB port, try another port.
  7. I discourage people from using a cable to transfer images from a camera to a computer. For one thing, it introduces more complexity. Your PC uses drivers from your camera manufacturer and a cable is one more thing to keep track of, and it’s slower. Again: direct is better. However, if you’ve run into a problem with your reader, it’s worth it to try again with a cable.
  8. When you import, lock the write tab on the side of the SD card. This prevents you from over-writing or deleting the images on the card until you’re sure you’ve imported the images.
  9. If you use Lightroom, it consider copying your images from the card to a temporary folder on your computer, inspect and delete the obvious duds, and then import  (ADD) from there. I use ACDSee  to inspect images. It’s much faster than Lightroom.

In addition to formatting your cards each time, another preventative measure, assuming your camera can write to two cards, is to make the second card a back up, so you have two copies of the same image file. And, while it won’t prevent card corruption, this is another reason I prefer to use smaller capacity cards (32GB) and not fill them before putting in another card. If there’s a problem, I won’t lose a full day’s efforts.

If you do experience this, consider tossing the card. Unless you’re absolutely sure of the cause, you’re better off spending a few dollars on a new quality SD card then taking a chance.

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