I have been using generax after an inferring single gene trees using pargenes, and preparing my families file with the script supplied.
I noticed that my around 3318 of my families were classed as invalid.
I checked the pargenes output for those families and it looked ok.
But focusing on one example, I noticed that pargenes had selected model LG+I, but the families file was listing the model as LG+IU.
Sure enough, every failed family was listed as a model with "+IU" in the families file.
Possibly just a bug in the script for preparing the families file in pargenes, but thought it might be useful for people to know.