1/3 of my Hawaii pictures were on a 512meg Memory Stick, and when I got home I couldn't load them! I was pretty freaked out, but in the end I was able to read them no problem off an XP machine at work. Not sure why that made a difference, but it did. I formatted it in Mac OS with zeroing enabled, and decided only to keep it around for emergencies. Well, I ran out of space today shooting, and I used it for around 30 pics. When I got home, it had 143 pictures on it. Mostly from Hawaii. Hummmm. Should I throw it away?