When I sailed yesterday, it appeared there was no track on the SD-Card. Reinserting it gives a 'unknown card'. I cleared the card and formatted it on the pc, but to no avail. Formatting it on the gps itself gives a 'fail' followed by a '-32768.aah'. I tried other SD cards, but no card is accepted. I tried reading it out by Navlink II, I can make a clone, read the settings and user data, but I cannot get data from the datalogger. Any clue highly appreciated!