Prevent Memory Card Errors

Visit any photography forum and you will find regularly that a member has a corrupted memory card and is desperately trying to recover the images.
Besides trying to find advice on saving those files, they almost always blame the card for being faulty.

memory cards
sd, microsd and compact flash memoery cards

Why do memory cards fail?

The truth of the matter is that 99% of data corruption on a genuine memory card can be prevented.

Memory cards will eventually fail as they have a finite number of writes that can occur on the card. But this can take many years and a lot of writes to the card to happen.

But, for the general user and photography use, they should easily outlast the camera.

On the extreme side of things for specific use cases. Memory cards used in dashcams will fail before the device is replaced.
Dashcams require continuous writing and rewriting until the card is full. It is also located in an area can that can get pretty hot.
Heat is not good for electronics. Enough heat can melt the solder and cause lost electrical connections leading to failure. Chips that also run high on temperature are also prone to write errors.

On the general-purpose use of memory cards like those used in cell phones. You will rarely have someone complain about a failed card that is not handled and only left in the phone memory slot.

So what is the difference between phone users and camera users of memory cards?

For most cases of corrupt files on a memory card, it can be attributed to human error. A high percentage of errors can be prevented by following these best practices.

The first thing to do when you get a card is to test for speed and capacity.
Testing the card can tell you if there are any errors on it, if it is a counterfeit card and what the actual read and write speed of the cards is.

Use this program to test the card.

h2test 1.4 – Memory Card Tester

You will need a card reader that exceeds the speed of the card else you will never know the true speed.

Most laptops and desktops wilk have SD card slots else you can purchase a basic card reader on ebay for a few dollars.

Multi Card Readers on Ebay

Once you know the card is good follow the below best practices to prevent card corruption.

  1. Do not turn the camera off before it has completed writing to the memory card.
    Don’t be tempted to turn the camera off as soon as you have taken the photo to conserve battery power. Let the camera finish writing before turning it off.
  2. Be careful when inserting memory cards in card readers and devices the wrong way. Inserting it incorrectly can physically damage the card leading to an unreliable connection. This unreliable connection can be the cause of write errors.
  3. Do not use damaged or inferior cables in card readers and cameras. It sounds like common sense, but people will try to use these cables in data transfers. The best-case scenario is the computer will alert you to the malfunction, the worst-case scenario is the cable causes a short and damages the card.
  4. Not testing the card. If you buy a large capacity card, you may never fill it up or it will take a long time. If the card has never been tested for true capacity then you run the risk of using a counterfeit card. You will only know of a fake card capacity if you do attempt to fill it up.
  5. Filling up a card to maximum capacity. The last image or video may break the card if there is not enough space and it tries to write to the card. For example, your camera thinks the card has 100mb left on the card. You are taking a few bursts of photos and don’t exceed that value so your camera tries to write to the card. The card tries to find the space but it is having a hard time locating the final few megabytes to store the data. The last couple of megabytes may be available or not. The best practice is to try and not fill the card completely. When you have a break from photo-taking, replace the memory card with a fresh one to resume recording.
  6. Not formatting cards on a regular basis. A lot of people don’t format the cards on a regular basis. They delete images and copy and delete many times. Over time the card gets fragmented, it slows the card down and affects performance. Besides performance, you could be using a different file system between devices. Some times the difference can cause issues with writing to the card. The best practice is to format the card in the device you are using after you have copied the files and made a backup on your computer.
  7. Using the wrong speed card. Using a slow card can cause issues. If the camera is trying to write to the card and it cannot keep up. You can get file corruptions if the image is taking too long and you interrupt the writing process thinking it has completed.
  8. Using inferior adapters. MicroSD cards are becoming popular because they can fit in most devices. Adapters that come with the card are generally ok to use. Using damaged card adapters can cause issues because of intermittent connection issues.
  9. Reusing the memory card. Memory cards have a limited life span, they can only endure x amount of writes and reads before they fail. My recommendation is to buy a new memory card for every new device. Leave the old card in the old camera and use that as a backup. Memory cards also get cheaper, it may be tempting to buy the biggest one available but unless you need to capacity you are better off buying in the sweet spot in terms of capacity. You generally get a better price per MB of capacity and also an established product that would have many reviews to confirm reliability.
  10. Disconnecting card readers or removing the SD card prematurely.

Follow these basic best practices and you should never have to run into a corrupt memory card.

Can SD, micro-SD, Compact flash cards Fail?

Memory cards do eventually die from wear and tear. For the average user, this is rare. For professional users, they will encounter this more often, which is why they should always use a camera that has dual slots, especially for critical photoshoots.

You will also get other failures where the entire card fails, you will not be able to read the card at all and the computer will not detect it. In those cases, an electrical short may have occurred and damaged the controller or physical damage. The card is toast and you will need a data recovery specialist to seem if any files can be recovered. These hardware issues are rare but do occur.

Another point of failure is fake cards. There is a common scam where cards are sold as higher stated capacities, but some modifications are made to the controller to show a different number to the actual true capacity. The memory card will work up to 90% of the capacity of the card, and then everything you write to the card afterward will start to corrupt the rest of the data on the card because there is physical no memory space left for the new data to reside.


These can be fixed but require a bit of research to identify what was changed. These cards should not be used and instead framed so it is a gentle reminder to buy from reputable sources and always test new cards for true capacity.

By Trung Tran

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