Same problem for me here
busy usb port, I searched through the whole forum, installed and uninstalled the FTDI driver. But with no luck.
It did work until this morning: since then arduino program keeps giving the same error message:Serial port 'dev/cu.usbserial-A4001aGv' already in use. Try quitting any programs that may be using it."
So i am not able to communicate with the Arduino anymore. What am i doing wrong? Some help would be great.
I have an intel mac. v. 10.5.4
Arduino NG ATMEGA8
FTDI driver version 2.2.9 (i also tried it with 2.2.10)