Arduino Due: Board at COM1 not showing

I have just received my Arduino Due and I have plugged in my USB cable. The ON LED is green and the L LED is flashing yellow.
However the port does not seem to appear in the list within the IDE, so I cannot upload any sketch. The cable is fine, it is the same I use for my Raspberry PI. However I find it very fiddly to insert, it is like the socket was narrower than necessary.
I have used a UNO for quite a while, so I know how to attach an Arduino e how to select the port, etc.
I have followed all instructions I have found around: selected the DUE Programming Port on the board list, inserted the cable into the right socket. I wonder if I should conclude that the board is somehow broken.

I am on a MAC with Maverick.

Any help gratefully received

Thnka you for me understand

I tried three cables and the third one works. Apparently my board has a slight imperfection in the two usb ports and only one cable clicks in properly.