Arduino + Macbook issue


I have a student in my Intro to Physical Computing class that is having issues with the Arduino when uploading where it tends to power down his macbook. It was only the Leonardo that was doing it, and now the Uno Mega and Decimilinove boards are not working either.

His is running Lion OSX on his machine. No one in the class is having issues with the uno and decimilinove boards. But a couple of students using PC and Mac have noticed that the Leonardo board will power down their laptops when using specific usb ports and only when uploading

His isn't using external power supply so he couldn't have overloaded the usb port, but it seems that somehow uploading to any of the arduino boards is shorting out the usb port now on his specific computer.

Is this a driver issue?