M | Audio Axiom 25 Driver [portable] Download Mac Top

The USB cable is likely drawing power, but data isn't flowing. Go to Audio MIDI Setup (Applications > Utilities). Click "Window" > "Show MIDI Studio." If the Axiom 25 icon is greyed out, click "Rescan MIDI." If that fails, you need a powered USB hub. The Axiom 25 draws high current; modern Mac USB ports (especially on laptops) undervolt it.