The Arduino UNO is not functional and in fact when you have 10.7.5 an error such as: “Serial Port Already in Use” /dev/tty-ZCASDFASF in my case: /dev/tty-EdwinHernandez-1 is already in use may prompt. However, this is not what is going on.
The USB on the Arduino from OSEPP UNO R3 PLUS is not listed in the VID/PID of the FTDI Driver for the MAC
You MUST upgrade the FTDI Driver to get your Arduino to mount the proper /dev/tty.usbmodem driver
The link can be found : http://www.ftdichip.com/Drivers/VCP.htm
And I used : x64_2.2.18 was installed, then I can see
/dev/tty.usbserial-AD01V379
And work with Arduino UNO R3 From OSEPP.
As you can see the MAC OS enumerated the wrong thing /dev/tty.EdwinHernandez is NOT the right thing, usbserial or usbmodem should be the one that is enumerated to work correctly.
Note: I also read about the /var/lock directory that needs to be done:
$sudo su –
Enter your password here!
#mkdir /var/lock
#chmod 777 /var/lock