I went to update my GPS SD card. It shows 6388mb used with 7572mb total space. When I did the update it sat at waiting to finalize the update for over 1 1/2 hours with no advancement. My question is this, should I format the SD card to rid it of all the used up space or will that screw things up? It makes sense to format it but I'm a little hesitant without asking the experts first. Thanks in advance for your input.