Genuine Nano with High Sierra solution ?!I have an update on this since my last post. I have got the nano to work purely by accident. I have both a genuine Uno and a genuine Nano connected to a Minix Neo USB C to USB B adaptor. By accident I uploaded the sketch to to the Nano with the board etc to Arduino/Genuino Uno. This works perfectly and I can decide which Arduino to upload to by simply changing the Port selection back and forth.If I set the Board to Arduino Nano then the MacBook won't talk to the Nano.To confirm this I have shutdown the machine and rebooted to make sure this wasn't some odd one off. I have successfully uploaded the sketch using both the Minix Neo and the genuine Apple USB C to USB B adaptor.So to be clear:I have:Arduino Nano (Genuine from Arduino.cc)Macbook Retina 12 inch 2017 - 256MB, 1.2 GHz m3High Sierra 10.13.4Arduino software 1.8.5Board set to: Arduino/Genuino Uno(not Arduino Nano)Port set to: /dev/cu.usbserial - A600MY5SThis is doesn't seem right but its working for me.Chris.