Understood. The issue is that I would like to monitor Audacity through headphones and Software Playthrough of input looks like the only way to do this but it locks up the application. Would this be considered a bug as it only occurs when recording with 4 channels. 1, 2 and 3 channel Software Playthough works fine.
Sorry for the double post BTW. I posted this same reply on https://forum.audacityteam.org/t/why-can-t-audacity-record-all-four-of-my-microphones/62719/1 to help another user.