Note that I have only tested this with macOS 13.4.
- Plug in both the power and USB cables of the Tascam, but don't power it on. It should be in "standby" mode with a green USB light, but the "power" light should only be dimly lit as opposed to fully lit.
- Press and hold down the "Sel" and "Aux 5" buttons. While holding them down, power on the unit; you should see the Aux 5 button blink 5 times. This means that the unit is in "Native Mode."
- In Cubase's MIDI port setup window, uncheck all the Tascam US2400 ports from the "In all MIDI" column.
- Create 3 Mackie Control devices in Cubase's Studio Setup window. Assign the input and output of Mackie Control 1 to port 1 of the Tascam 2400. Repeat this for MCs/ports 2 and 3.
- Be sure to select the "Reset" button in each of the Mackie Control device windows.
Everything should now be working!