Can I keep using a corrupted SD card?

Question

So I just came back from a shoot, put my SD card in my card reader and copied the files from the card to my computer. At least I tried to, but after the first image Windows reported an error message that the connected media was not formatted in a recognisable file system.

The photo recovery software is running now and it looks like I've gotten lucky this time. Now I'm wondering if I should toss that SD card or if it's a good idea to try to format it and continue using it. I.e. is it likely there is something physically broken, or is it probably just a random error in the file system that can be fixed by formatting the card? It was a pretty expensive Sandisc Extreme 64GB card, so I don't feel like just tossing it (I bought it through Amazon, not sure if any kind of warranty applies …)

Answer 1

Can I keep using a corrupted SD card?

Well, you could. But you might not like the results from doing so.

Based on the rest of your description, though, before you toss the card you probably need to establish that the card, and not something else, is the actual source of the problem.

Here's a checklist of things you should look at:

• How was the card originally formatted? You should always format a new card in the camera in which you are using it. (Note: you can also format the card with a computer as long as you use the correct file system and create the correct folder structure that the camera requires - but it is a lot easier just to use the camera to automatically do all of that.)
• When was the last time the card was reformatted? Not reformatting flash memory cards periodically can lead to file corruption. When a flash memory card is formatted the controller maps out sectors marked as bad so they are not reused.
• Have you confirmed that the card reader is not the issue? Do other cards have similar issues? Or do other cards work fine?
• If the card reader is a portable one, have you tried using a different cable to connect it to the computer? A different port?
• Have you recently updated the USB (or Firewire, or whatever interface you are using) drivers?
• Did you remove the card from the camera or card reader while the card was being written to? This can cause corruption of files. It may or may not have also damaged the hardware of the card.

If you've eliminated each of these possibilities then the chances are pretty good the card was corrupted.

Answer 2

In a comment of yours I read "@MIchaelClark I always format the SD card with the camera before a shoot, always with the Deep Level formatting option as well (Canon EOS system)". "Always [...] before a shoot" sounds like "more times than I remember" and "Deep Level formatting option" sounds "in a manner sure not to leave any recoverable sensitive data on the card by overwriting the entire card".

Uhm, you are aware that flash memory has a limited number of write cycles? The "Deep Level formatting option" is something you use before selling or destroying an SDcard or before travelling into a country which might prosecute you based on prior contents of the card.

Doing it before every shoot means that every shoot produces the wear and tear of completely filling the card with photographs once.

Whether your card corruption is a fluke or possibly attributable to wear is something only you can judge. Modern cards should actually have ten thousands of cycles before becoming iffy so my guess would be more about removing a card when the camera/cardreader was not yet ready for it. If you are reasonably sure it was just a one-off, a normal(!) reformat should be enough to get you back in business.