Hello,
I saw a few posts about something similar from a decade ago, and after trying everything in those posts and nothing working, I decided to make my own.
I've been playing with this family for a bit now and everything was okay. I have a lot of mods but I try to stay up to date with them and do my best to keep them organized. I've already tried taking my mods out to fix the issue and repairing the game, even deleting certain files, then repairing it so it resets some things. The issue is still happening.
After the last update that happened a day or so ago, nothing seemed broken except a UI mod, which I have since found and fixed. Until I tried to load my game another day later. Now, whenever I load into my game, my family is grayed out and unplayable. It says they are at home, but they are nowhere to be seen. I had downloaded some big packs of CC, so I deleted them, wondering if that was affecting it. The issue persisted. I tried everything I could find online and eventually found that if I evicted my household and moved them into a new lot, they would appear again. It loaded perfectly fine a few times. I decorated some of the rooms, using CC as well. When I take the mods and CC out, it still persists. Eventually, when I tried loading the world again to see if it was okay now, two of my sims were deleted from the household, and they also did not appear in the relationships section for my sims. I know it's not an older save for my family because my sim is still pregnant. Both of the sims deleted are werewolves.
I have the family saved to my gallery, so I still have them in case that helps at all. I will continue to test some things out to see if I can figure anything else out. I do have a large amount of mods and CC, so I will run some tests with those. Let me know if you need anything specific or any more information. \
Thank you,
Lia Rose