Arduino Nano on Mac

Hi, I have the following error trying to use Arduino Nano on the Mac. Also installed some FTDI driver but with no effect.

Anybody had this issue?

Arduino: 1.8.4 (Mac OS X), Board: "Arduino Nano, ATmega328P"

Sketch uses 9044 bytes (29%) of program storage space. Maximum is 30720 bytes. Global variables use 531 bytes (25%) of dynamic memory, leaving 1517 bytes for local variables. Maximum is 2048 bytes. avrdude: ser_open(): can't open device "/dev/cu.51949-SerialPort": Resource busy Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.

This report would have more information with "Show verbose output during compilation" option enabled in File -> Preferences.