Background Task:
I created an Ubuntu Live USB stick, using start disk creator app of an Ubuntu machine that I borrowed. The Ubuntu version is the latest 18.04.2.
I would like to plug that USB into my Mac air(version 10.14.5 Mojave), and boot from it to install linux on another USB (also plugged into the Mac).
However the USB with the Ubuntu Live can't be read by my Mac. I get the message "The disk you inserted was not readable by this computer". So I have not tried to boot from it.
I think I may have to use the method described here to do what I need to do
Foreground Task:
I am guessing that I will have to recreate a boot installer on the USB the has ubuntu Live. I am unable to even reformat it and reuse it.
How can I get my Mac to detect it so I can reformat it ?
I have checked other posts, and found this duplicate question : no clear answer, but it is 9 years old and am not sure how current the advice is. Also the answer makes reference to chipset support issues with newer laptops.