Re: The Sims 4 Island Living Sulani world not loadind, and I can't make mermaids
Are you using custom content or mods in your game ? If so, have you tried removing those ?
A lot of custom content/mods is outdated and needs updating.
Try removing everything and see if it then works.
If it does, narrow down which one it could be
Use the 50/50 method: http://modthesims.info/wiki.php?title=Game_Help:Finding_Problem_Custom_Content
Here's a list that can help you find the problem ones: https://forums.thesims.com/en_US/discussion/960932/broken-updated-mods-cc-island-living-june-2019-patch#latest
