My DAW (or Hardware VU) crashes
MackieControl INPUT: None
MackieControl OUTPUT: your virtual MIDI port.
Using Bitwig? It doesn't let you do Output only, so make a second virtual MIDI port and assign the input to that.
The grid shows clip slots instead of VU
Ableton claimed the Launchpad as a control surface and is sending it clip-launch commands instead of meter data. Find the Launchpad's entry under control-surface preferences and de-select it.
Pick your controller
Plug in your Launchpad and choose it from the LAUNCHPAD dropdown. The four circles beside the label are orientation markers — pick the one that matches how you've placed the controller so the meters always read bottom-to-top.
Check your audio source
Open AUDIO SETTINGS… and confirm the right device is selected. To meter your computer's sound, you may need a loopback or virtual audio output.
Turn up BOOST and watch it go
Turn the BOOST knob up from 0.0 dB until the grid starts reacting. Use STYLE to change how levels map onto the pads — Left, Center, Right, Wide, and Butterfly. Tick MONO to sum both channels into one meter.
MCU mode displays your DAW's first 8 channels over a virtual MIDI port — no audio routing needed. Requires a bit of setup.
Create a virtual MIDI port
On Windows, install loopMIDI and create a new port. On Mac, open Audio MIDI Setup, open the IAC Driver, and add a bus — Ableton's guide walks through it clearly.
Connect in Hardware VU
Click the MCU METER tab. Pick your Launchpad from LAUNCHPAD, then pick your virtual port from VIRTUAL MIDI PORT.
Set up MackieControl in your DAW
In your DAW's MIDI or control-surface preferences, add a MackieControl surface. Set Output to your virtual port and leave Input as None.