I am using the CH340 drivers downloaded from here:
It works with the cheap nano clones - the port is detected by the Arduino IDE and I can communicate with the Arduino, but inevitably my Mac's screen will turn white and a message saying that my computer has restarted will appear. Sometimes the restart happens right when I plug in the device, and other times it happens only after I use it a while. It happens with both the Nanos and the Uno clones and it also happens with the Nano/Uno "out of circuit" - i.e. nothing attached to it.
I'm running OS X 10.10.3 on a Mid2010 MBP w/ 16 GB RAM.
Has anyone else experienced this?