I was in the middle of a photoshoot with my Nikon D7000 using a 16GB SD card, when I receive a card error.
When I insert the card into the Nikon D7000, it reads it briefly, and then it says "Card Error." Card is corrupted, please insert a different card.
When I insert it into my computer's built in SD card reader, the LED light next to the drive stays a solid green; it's trying to read it but it can not. It does not show up on the computer's drive. The computer cannot even recognize that the card exists in the computer. I know the SD card drive is F: but there is nothing there.
Alternatively, I try leaving the card in the camera and then connecting the camera via USB into the computer. No luck. The computer cannot see anything in the card.
Memory cards have a limited lifespan. if there's nothing on it you really need, just throw it out and replace.
Even if you managed to access it, it would continue to give you problems, and a card that can't be trusted to be reliable isn't worth the risk.