I have had similar problems with the pro duo memory. I was using an adapter for a Sandisk 256 meg card. I plugged it into the slot, and it displayed fine at first. Explorer showed the images that were on the card. I did a copy paste from the card to my computer, and that's when weird stuff happened. It gave me some... error... that I don't remember, then it stopped working. It only copied over one of the images. I took out the card, and plugged it back into the slot, and it told me that the card was not formatted. That's odd. So I plugged the card back into my camera, and it gave me an error number, one that I also don't remember, and would not let me reformat the card. SO my camera couldn't format, or recognize the card, and my computer couldn't format or recognize the card, so I was frustrated to find that my card was no longer useable. So I took it back and exchanged it for a new one, and I haven't had the nerve to really try it again since I'm afraid that this reader will eat up another card... All I can say is that I have noticed some odd activity when it comes to the pro duo cards. I have used the CF slot and it works wonderfully, but the pro duo just doesn't work right. Go figure.