Bought some crappy Nano knock-offs recently and I couldn't find an open port on my Macbook Pro OS 10 High Sierra.
Spent a week trying to understand why, reading forums etc downloading the latest updates, but supported Arduino by buying an Arduino Genuine Nano, meanwhile I tried my trusty Uno which did find a open up a port when I plugged it in.
The Nano came today - fantastic delivery service Arduino - which is another great service - and this works too......
You all get the moral to the story.
Happy days.
Thanks for your support of the Arduino project!
The Nano is a great board. Definitely worth the Arduino Store price.