I have a Sony Cyber-shot DSC-P31 and am now getting this C:13:01 error on one my memory sticks. I wasn't too worried about loosing my pictures because the first thing I did was took the memory stick and stuck it in one of these USB reader/adapters and downloaded my pictures by-passing the camera. Then I tried to format the memory stick from the camera, but that would not work. I still get the error. So I formatted the stick in my adapter on my desktop computer which worked fine. But the camera still tells me that I have an error C:13:01. Now I believe that something is wrong with the camera. I tried Kevin's idea of reformatting the memory stick like using this command "format F: /FS:FAT /A:8192" but that still does nothing for the error on the camera. I just thought I'd get out the memeory stick out of my Sony Clie and start using it instead of the bigger memory stick that was in my camera. Guess what, I still get the C:13:01 error. It has to be in the camera and not in the memory sticks. These memory sticks are true Sony memory sticks and not Lexar's or anything else. Are there any other ideas?