Turn off all activators when closing Vmix so that all the lights on the Midi device at turned off or back to default,
Turned back on when the Vmix Preset is opened again

I have noticed a issue with my APC Midi and the lights don't always work unless I log out or restart the pc after plugging it in.
Log out resolved the issue. This could be at previous Vmix session or Windows has not got control of it ???