Due appears as COM6 port but gives error "No device found on COM6" on upload

Hi all,

The correct value for the R23 resistor is 1k ohm. R23 resistor is used to adapt the 5V logic of the 16u2 to be compatible to the voltage logic of the SAM3x, the 10k ohm gives completely wrong values to the reset pin.
I want to figure out if it happened a mistake during assembling.

Can I ask to those of you who have experienced the problem to write me the serial number of the Due, you can find on the cardboard box?
You can reply here or write me an email (f.vanzati at arduino.cc)

NB: the serial number is not the number written below the bar code, is on a separate sticker.

Thanks,