vaj4088:
Power supply issue? Problem with some other device?
Power is supplied via USB cable directly to my Arduino Nano. No other devices are connected to my MacBook Pro and up to now I hadn't any problem with my MacBook.
If I connect another Nano and upload the sketch above, the result is the same.
The problem occurred also, if I use a separate power supply to the Nano (like a powered rc receiver which provides the arduino with 5V).
Which information do you need more?