alinmesser:
I tried both the programming and native USB ports, in a Windows 7, Windows 8 and two Linux machines, but my new Arduino Due is not detected. The power led is on and the L blinks about once a second - which seems to be the factory sketch loaded.
I also tried to power it differently, with a 850mA/5V adapter, and a 2x to one USB Y cable with no luck.
I would have thought the ATMega16U2 was bad, but if that was the case why isn't the native port being detected either?
I'm a new user and really don't know what else to try.
Try connecting using the native usb port. Then press the erase and the reset button at the same time. If everything went well, the bossac port will connect to your pc. You can upload a random sketch with the arduino ide then. After that, press the reset button again. And everything should work again.