Port Not Being Found Hey everyone I know this is a pretty common question, and I have read/tried almost everything on all the other posts here and on the arduino.cc forums, but I have been unable to fix my problem. Basically I have been using my Arduino Leonardo for a little over a month now for all sorts of things and have never had this issue with the Arduino not showing up under the port tab on the menu. I have no idea why this just started happening to me, I am using the same cable, etc, and was hoping someone could help me out. I am on a MacBook Pro by the way. 

Thanks in advance.
Try this...
Go to your Arduino IDE.
Under the Tools tab, go to "Board" and select Arduino Leonardo.
Then in the Tools tab, go to Port and check to see if a port is selected.
Use this link to try and find which Serial Port you should have: https://www.arduino.cc/en/Guide/MacOSX
Try plugging in the cable in different USB ports on your computer and see if the port number changes automatically.

Also, could you please say what peripherals or other things are connected to the arduino? Because for example, I know what using a Bluetooth slave with the Arduino while connected with the cable to your computer, doesn't let you upload your program. There could be similar problems to this.