I ran into the same issue when I first tried to use mine...had to do a nearly comical voodoo dance of plugging in USB and power in different orders till I got it to see the device. Then an entirely different set of shenanigans when I tried to update firmware.
I believe what ultimately worked for me was having the AudioFuse Control Center open and running, firmware update already downloaded and waiting on my mac, plug in AC power, then plug both usb plugs into mac and cross your fingers.
Update firmware right away by navigating to the packet and running upgrade.
Once I got through this it has been relatively stable ever since, other than my previous posts regarding sleep/wake and conflict with internal audio.
I will say I had to plug in and unplug repeatedly for about an hour before I could get it my mac to recognize it originally.
Good luck.