Strange card behavior

I have a SanDisk Extreme compact flash 16 GB 60MB/s card that I use in my 1D MK IV. Has been fine for about 2 years. Took it out and could not read it. (Card reader is fine).  Put it back in the camera and message said it could not be read-eject or reformat. My husband managed to extract the pictures- one had a white rectangle in the corner, the rest were OK. . Put the card back in the camera , reformatted, and now it is working, but I don't trust it.  I guess I can keep using it  along with an SD card in the camera for backup-, but wondering if it's going to blow again.  I assume 2 cards will also slow down the camera a bit? Anyone else have that sort of experience?

Thanks for your thoughts.

This is the most common kind of storage card failure, and most likely it means nothing bad about the reliability of the card. It simply became corrupted for some reason and was not readable by the computer or camera, but not because of any hardware problem. Just the organization of the data on the card. So keep an eye on it but it's most likely still usable.

If you're more concerned, you could do a slow / low-level format on the computer, as opposed to the quick format that's done in the camera or by default on the computer. A low-level format will check for deeper errors; if none are reported the card is probably fine.

Royce Howland wrote:This is the most common kind of storage card failure, and most likely it means nothing bad about the reliability of the card. It simply became corrupted for some reason and was not readable by the computer or camera, but not because of any hardware problem. Just the organization of the data on the card. So keep an eye on it but it's most likely still usable.

If you're more concerned, you could do a slow / low-level format on the computer, as opposed to the quick format that's done in the camera or by default on the computer. A low-level format will check for deeper errors; if none are reported the card is probably fine.

Thank you, Royce. Very helpful-I'll try the slow boat.

After doing a low level format via your computer and card reader, if it is successful, then format the card in your camera. That will apply the special folders and structures the camera uses. The camera format is a special quick format.

http://kb.sandisk.com/app/answers/detai ... 20software

In addition there is a notice that after a date in 2012 SanDisk no longer supports RescuePro. It would not hurt to try a trial copy to see if it can recover anything. I received a coupon for that with a Kingston flash card some time ago. I've never had to use it fortunately.