Official comment
Hi Maria,
If the DDJ doesn't show up under the USB devices in the Applications > Utilities > System Information app, then the problem is either with the USB port, the USB cable, or the DDJ itself. If you've swapped the cable, tried another port, or even tried another computer and it still does not appear, then the problem is the DDJ itself. In that case, please contact an authorized service centre in your region to have your hardware inspected and/or repaired.