After inserting a used SD card into the camera and attempting to view the footage, the words "NO DATA" appear on the screen. There is only 1 minute left on the card, so I know the footage is on there! I rolled another 10 second clip just to see if the card was still working, and now that is the only clip that shows up when I view on the Mac or in the camera. Anyone have any ideas how this can be remedied? Thanks.