I use sandisk cards as well, I was using a 2gb card but I was getting a green coloration on several pictures so people suggested using the 1gb. My cards have been swapped between my moultrie, pentax digital, and my cuddeback. I don't know if by doing that it can change the cards configuration and no longer work in the camera. Last year I pulled the card in the field and viewed them on my pentax. This last time I formatted it, set it up in my kitchen, walked by and it flashed, I pulled the card and the picture was there. I put the card back in, walked by and it took another picture. I put the card in my pentax again and this time my digital said no data available. I don't know what the problem is. One time it works, one time it doesn't.