This kind of thing should be easy right?
I have a SatNav and a computer.
The first problem requires a spotters guide to USB
Types of USB Connectors
While USB is the Universal Serial Bus there are lots of combinations out there.
Type A is the usual one used by plugs. Type B used to be used by some printers. Mini is used as the power supply for some devices. Micro A was used for older android phone and kindle devices. Type C is the modern EU approved standard version that is used by all modern phones.
The fun part is that the Garmin has a cable with type A at one end and Mini on the other (this is the end the goes into the Sat Nav). Mac currently only support USB-C. This is fine as I have an adapter.
The first A – Mini cable that I used (because it was in the house) did not work.
The Garmin Express helpfully suggested not using a hub and directly connecting to the computer!
The second A – Mini cable that I tried was in my car (and was the official cable). This one works.
Lesson learned: Mac port adapters do work with Garmin!
It is also weak at estimating download times. What started at 2 hours is going to only take 15 mins.
Developer Rants 