My computer restarts sometimes when I load a sketch

I don't know why, my computer restarts when I upload a sketch.

I am using an Arduino Leonardo clone (flyduino pro micro), my computer is a MacBook Pro running mavericks (10.9.4).
My sketch is for controlling a quadcopter, so it uses libraries for sevos, gyros and PID regulator.

Any help?

Thanks a lot!

Are those servo motors connected ? Is perhaps an external power supply connected ?
Try the new Arduino IDE 1.5.7 BETA, with a new USB port and only the bare flyduino board if possible.

It happens sometimes. When I has testing the motors it was ok. But reading data from the sensor (Wii Motion Plus clone), I have problems: It runs ok at the first time, but at the second load I get a different output (It looks like not executing void steup(), and runs only the loop). And some other times it doesn't run and my computer restarts.

If I test the flyduino board separately it is ok.

The problem seems to be solved. I think I was overloading the serial port with too many output messages. Using delays or meters solves the problem.