Keeping Your Memory Cards Healthy

KEH has published a helpful primer on memory cards that describes the different types, common error codes you might come across when using them, and how to take care of them:

Memory cards are quite sturdy and commonly expected to work through one million read/write/erase cycles. The weakest part of the card is the connectors however, and should withstand around 10,000 insertions/removals into a camera or card reader.

No matter which type of card (CF I&II, SD, XD, SM, MS, etc.) your camera takes, it’s a good idea to format it on a regular basis. While it may not happen often, these little cards of information can fail and reach the end of their life unexpectedly. To keep your card in good health, format it in the camera from time to time. (I format my card after every major download). This clears up the card and erases all of the data. Of course make sure that you have downloaded and saved onto a computer all of the files on the card before formatting.

Since the number of insert/remove cycles a card can handle is far less than the number of read/write cycles, it’s very important to handle your cards gently in order to prolong their lifespan.

Memory Cards: Compatibility, Error Codes, and Health (via Photojojo)

P.S. Last month Canon also published a helpful guide on its cameras error codes and what they mean.

Image credit: 4GB Memory card by Jorge Quinteros

  • Oliver Lea

    I would hope this was common knowledge, but also, I would consider ‘formatting after every major download’ as serious overkill. Solid state memory isn’t that crap.

  • Markus WET

    I format the SDcards in my D7000 everytime after shooting & importing to my harddisk. It’s just a convenient way to delete all files from the cards ^^

  • guest

    I don’t think too much formatting does any good, I know SSD drives don’t like it too often, not sure of memory cards.

  • W Feilner

    It may be better to format your SD card instead of deleting the files. The delete command will write to the FAT once per file while the format operation is a on stop shopping. However, a normal format will not erase the data from the card completely. In terms of (hidden) data left there is no big difference between deleting all files and formatting the card.

  • jdm8

    I rarely format a camera flash card.  I can see it being useful occasionally, but every major download seems like too much.  10,000 insert/remove cycles is over 13 years if you shoot on the card once a day, remove the card to read on a computer, then put the card back.

  • wickerprints

    The article assumes that you only read/write to each sector of the card once per use, hence the claim that insertion/removal is a more fragile operation for the life of the card.  This may usually be the case, but it isn’t necessarily true.  If you read/write the card many times before removing it from the device, then the situation is reversed.  Examples include reviewing the images on the camera, or deleting unwanted shots.  Furthermore, all it takes is for one sector of the card to fail before it becomes untrustworthy.  As cards get larger, the probability that at least one failure occurs increases even if the probability that a given sector fails in a given period of time remains constant.

    Also, formatting doesn’t delete the data.  It only erases a small part of the card that contains the data the filesystem uses to locate the individual files.  Formatting is a good idea because it prevents the filesystem from becoming corrupted.

  • aptguy01

    “To keep your card in good health, format it in the camera from time to time.”

    seriously ??? Still 23 days to go before April 1st.

    Its also a good idea to oil the pins every few hours…

  • Cochese

    If you are worried about card health, pick up one of Samsung’s metal SD cards. They are suprisingly cheap and have about the same speeds as Sandisk’s best.

  • Schnitzer17

    I believe formatting after each download has another purpose, as well.  I may be explaining it wrong, but the file names (for example DSC001) continue from the last file named even if you just deleted the images on the card, but formatting actually resets the counter to 0.  As I understand it, once those files count up to a certain number, you’re out of luck.  Kind of like how they say that when you delete something off your hard drive, it’s not really gone, which is the idea behind hard drive scrubbing or shredder software that actually erases it multiple times or writes over it with something else.

  • Spi13

    I format my cards every time I use them, and I have never had an issue other than physical………..I broke a pin on a 40D…………that sucked!

  • Johnecono

    I am a computer person (30+ years in IT), and formatting rewrites the FAT (File Allocation Table) on a drive or memory card.  Just deleting the data leaves all the FAT entries there (albeit with a delete flag), and new files (photos) written just add to the FAT.  Eventually, if you never format, eventually your FAT will fill up & hit the limit of how many files it can contain – – – as well as using up more of the space on the card to just hold all the locations of all the deleted files.  Having a large FAT also impacts file write & retrieval times – – it is just an index file, and large indexes take longer to find what they are pointing to than smaller ones.

  • Jharderfsd

    What do you think memory cards are? Just little sad drives…..

  • Jharderfsd


  • nicewinterweather

    my card is not reading on my desktop or laptop or on one of those portable card readers   is there any place that i can take it too to retrieve my pictures?  dose not give any error codes in camera just says no memory card  i live in Sterling hts mi

  • Werner

    Actually this is not true for all cameras, some will continue with the subsequent number of the last shot, even if you will insert a new card. Actually I prefer this way, because I get a unique number of each image until it overflows.
    There are usually four or five digits. What will happen after 999 resp. 9999 shots? It will start at (0)0001 again simply. To not override the first shot if not there, some devices distribute the files in numbered folders (actually they do it for other reasons, but this is another story).
    The number that counts is the number of writes per cell. But there is no way to know which cell will be used for a given file …

  • Werner

    Hmm, I can’t beat your three decades in IT, but I believe you are talking about the root directory, not the FAT (file allocation table) itself. The flags in the FAT have to be cleared to show the corresponding sectors are free. The directory entries will be marked as deleted, but kept mostly intact, that is correct. However, I never heard that a directory got an overflow. Any good OS will reuse deleted directory entries sooner or later. The bad ones will recommend frequent formatting. 

  • Werner

    Reading the data will not cause any damage usually. It is the writing and deletion of data that is the limiting factor. It could be better to format the card after fetching the files from it instead of deleting each file seperately.

  • diane

    i do low level format on my canon t3i every time i download. that is what the manual said to do. i use a 32 gb card and never take it out of my camera. my camera gets connected to the computer directly to download. i bought a pricey card-belkin i think? from b and h over a year ago. so far, no problems. i do have an occasional corrupted file.