@dereneaton and @isaacovercast I checked the toytree version and I am running v.0.1.6. I am not sure what kind of rule of thumb exists for how memory requirements scale for the number of taxa. I tried running just 400 quartets on a dataset consisting of 353 taxa on a node with 125gb of memory. The run failed after just 43 seconds during the "intial tree" calculation. So given that I am running the correct version of toytree, could memory be the issue given the number of taxa in my dataset or something else?