Follow should help with following –
a) Connect you new UNO R3 based Arduino board with you Mac OS based system
b) Fix if your UNO R3 based board is not being recognized by your MAC OS.
c) Your UNO R3 board GND led is flashing continuously with any uploaded code.
d) Your Mac OS serial port is not recognized on Mac OS yosemite.
e) Definite guide if you are using ELEGOO UNO R3 with Mac OS yosemite.
Open terminal & run –
/usr/sbin/kextstat | grep FTDI
If it does not show anything, it means that the Mac USB port isn’t talking to your Arduino/UNO R3 board.
The definitive solution found was following –
Download CH341SER_MAC-1.4.zip from somewhere (e.g. below link), unzip and install it (by double clicking on the pkg file) , reboot the system.
Now you should see something like below,
If yes, you should be good to start with your ardunio/UNO R3 projects.