I used a 32GB sandisc and had all the same problems as you Dave. I lost some very important footage from a wedding that I'll never get back. Gopro said to reformat so I did. And re upgraded the firmware. I don't have the freezing up any more but I cannot fully trust this camera anymore. The 2 sec timer setting is more like 1 sec and I find the 5 sec is too long. The camera is warm to hot when using and when charging. Here is a file that I could not view, it had 1.07 GB of video but would not open. This happened 2 times during the shoot and gopro had no answers. All the other videos were great. I am very happy with quality and new options the gp3 has, its just now dependable!!!