- Unplug the controller from the computer.
- Open Audio MIDI Setup (located in /Applications/Utilities).
- Look in the MIDI window. If the MIDI window is not visible, go up to the Window menu up top and select “Show MIDI Window”.
- Look for the device named “USB MIDI Device” and click it. You may need to scroll to the right to find it — the window doesn’t appear like it should scroll, but it does.
- Delete the device by pressing the Delete key on your keyboard.
- Plug the controller back into the computer. A new device should appear in Audio MIDI Setup with the proper name you chose for it.