Rimworld takes about 15 minutes to load to the main menu when mods are present in the mod folder, active or not. It takes another 15 minutes or so to look at the mod menu, another 15 minutes to leave the mod menu. All other parts of the game work fine, a save loads after a few seconds delay. With an empty mods folder, Rimworld takes 20-30s to load.
EDIT:
I exited the mod menu after making this post. This edit signifies Rimworld having finished loading the main menu.
