I got my wife a slightly used 3100 recently and we are getting repeated false errors stating that the card is corrupted and cannot be accessed nor formatted, this with several different SD cards. Sometimes the camera reports the error after only a few shots, and sometimes after many dozens. When I put the SD card into a reader and access it from my Mac, all the images are there. I can then format it on the Mac and reformat it on the 3100 and all is well. It is definitely not a card problem, given that this has occurred with at least four different cards from at least 3 different manufacturers. As a side note, I have gotten the same problem on my 7000 but much less regularly. t would cost me a bundle to have NIkon look at the camera as I don;t own the sales receipt nor the warranty (they were lost, apparently) so I can;t even send it back to the seller to have him send it in. Anyone seeing this type of issue or have any suggestions. Thanks much. Dennis
#1. "RE: 3100 false card erros" In response to Reply # 0
I have gotten card errors with the D3100 a few times when I first insert it and turn it on. They have always disappeared after I reinsert it the second time. If your camera slot requires abnormal pressure to insert the card try using an old unneeded card and insert it and reinsert it 50 - 100 times to loosen it up. My first D3100 had that problem and I think that that may have caused the error messages, but I don't know for sure. I had to exchange my first one due to an inoperative video button.
You might try calling Nikon to see if they will fix it under warranty. If this is a known problem they might just bend the rules. Also, perhaps your seller didn't register it and you can then register it yourself. It's worth a try.