Put a "Stop Generating Random Townies" Button in the settings
Random townies in the sims are very annoying, i don't like ugly sims and it keeps crashing my game.
Forum Discussion
This is an annoying known issue, but not strictly a bug as far as I'm aware. The game is pretty heavy handed with townie generation and (apparently) also quite whimsical with townie culling. Limiting your max number of sims might help?
Honestly I keep Cas.fulleditmode on all the time and fix them when I find them. There seems to be an unending supply of them.
