Basecamp can't find 60CSx

Hello

I Have a new MacBook Air (only USB C) and Basecamp installed. I just noticed that Basecamp or any other Garmin Software can't find the GPSMAP 60CSx via USB. If I start the Masstorage Mode nothing happens. Even the DiskUtility can't find another device.

Since the device can't read waypoints from the SD card I don't know how to get my routs and waypoints on it.

Kind regards Jens