Endless loading screens have many causes. Please refer to this thread for more info: https://answers.ea.com/t5/Game-Issues/MASTER-THREAD-Crashing-and-Endless-Loading/td-p/13328880/jump-to/first-unread-message
First thing to do is remove ALL your mods/cc by moving the entire mods folder to the desktop and delete the localthumbcache file then try on a backup of your save.
If this doesn't help, please check for any lastExceptions you have and check if other households load.
It seems the issue is either the Sulani lot itself or the built I made on it. I tried a few things. Played as a whole new household; split my main household to see if the issue is them; moved an npc into that household then split it again to leave the npc with the lot/build then bulldozed the lot and then deleted the npc so that whatever glitchy thing might have ended in the household inventory didn't stay with my own sims. After all that I could load the lot in live mode and travel with sims to said lot just like normal. But everytime I tried to place my built back on the lot it started issues, like I couldn't switch floor anymore, I couldn't change the wall visibility. At this point I think something between that lot and building on it is causing the main issues.
