GPS Repair Problems? Ask a GPS Technician for Answers ASAP
Can you connect the Garmin device to any other computer and does it show up there?
If so, we can troubleshoot the problems on the Mac.
If it does not show up on any computer, then try using a different USB cable.
You may also need to clean out the USB port on the Garmin device if there is any debris stuck in there that may be hindering the connection.