All current Garmin devices, when connected to a computer, will communicate in either Mass Storage or Media Transfer Protocol (MTP) mode. If the computer is not detecting the Garmin device, there are a few troubleshooting steps that can be done.
The device should automatically go into Mass Storage or MTP mode, which is indicated by a picture of a GPS device connected to a tower on the Garmin screen.
To check the computer's recognition of the device on a Windows PC click on the Start menu and select (My)Computer. The device will show in this window if the computer recognizes it. On a Mac, the device will show as an icon on the desktop, labeled "GARMIN", or it can be found by selecting Finder from the dock and viewing the device list on the left-hand side menu within the window.
Note: If the computer still does not detect the device, try plugging it into a different USB port. If the problem persists, try another computer, if available. Ensure the USB cable is not connected to a cradle, if one is attached to the GPS.
Ensure the cable is a compatible USB cable. For more information on compatible USB cables, visit the article: What kind of USB cable do I need to connect my Garmin GPS to a computer?
If you still experience problems, contact Product Support.