Arduino port not showing serial USB Mac OS El Capitan I don't see serial USB as an option under ports when my Arduino is connected to my Mac. I have used this Arduino on the same computer before without any issues on Yosemite OS. However, I was trying to run a servo motor and I don't think I was getting enough power so I decided to use an external power supply. 12V 500mA DC and connected it while still keeping the USB connection. Since I already had the servo program loaded, the motor did work. Then I tried uploading the program again, that's when I realized that there was no serial connection. I am not sure if the problem is because of the power supply that I connected.

I tried the following approaches without success:


Upgraded the OS to El Capitan (which might have been a bad decision in hindsight).
Tried connecting the Arduino to another Mac with new Arduino IDE download, same issue.
Tried downloading the FTDI drivers as suggested by other folks.


I searched for a few hours for a solution online, but nothing so far has helped. Please provide suggestions.
Change USB ports
Check your Tx and Rx pins aren't connected to ANYTHING.
Reboot your Mac.
If you're really desperate, change OS.