Just recently had this happen to my main game save file. I have a small number of rentals comparatively, about 6 I think, both self build and used from gallery. Cheats enabled for show hiddwn objects, move objects, ingore game play unlocks, free realestate and free build. I did also own a small business and a resturant. I have a large family (not house hold size, but current HH size is at max 8) and built up the entire map of Newcrest. I lost all ability to see the properties, businesses and restaurant I owned in the small window in the bottom right of the screen with the cash register icon - owned businesses screen. However, when I go to the world map it still lists my character as the main owner of all the properties when i mouse hover over them. When I randomly bought a lot and set it as residential rental, even without building anything on it, my properties reappeared in the owned businesses window, but the second I left that property I just bought to go home or to any other property be it owned or just an in-game model property, they disappeared in the little owner box again. Below is a list of things I tried to fix the issue to no avail.

I uninstall/ re installed

I did a repair though steam

Changed name of save folder

Copied and replaced save folder

Made sure mods were up to date

Removed all mods

My other games (2) that used all the same mods / expansions and had rentals and businesses worked and had no issues. They are not as big as the game that is experiencing this save corruption issue. The game with the issues littlerly has my family size (not house hold size) at like 10 kids all as adults living in Newcrest with their spouses and kids in houses built or loaded from gallery. I was just getting ready to age up the next generation in hopes of working on generational achievements.

I do use the For Rent expansion and have since turned it off and had to start a while new save and game. It sucks. I was working on a lot of achievements / aspirations/ etc ilon my main game and to lose all that time is really disappointing. Made it really hard to want to jump into a new game and start all over.

Expansions owned at the time of corruption are: life and death, realm of magic, fitness stuff, toddler stuff, vampires, seasons, home chef hustle, spa day, eco life, island living, get to work, laundry day, perfect patio, the Sims 4 ep15 post launch edition key (no idea what that is but it is in the dlc list lol), for rent, simmates collection, comfy gamer, crystal creations, discover university, dine out, business and hobbies, set up shop digital content, cats and dogs, blooming rooms, greenhouse haven, my first pet stuff, awesome animal hats, digital deluxe edition key, hiloliday celebration, life of the party, up all night.

I really hope some of this information helps and that it gets resolved soon. I only recently experienced this issues and I can not imagine how people who have been dealing with this longer than me feel, I just know that the amount of money spent and time put into this, to have something like this happen and not be a front and center concern over releasing content to pad pockets is really a let down.

Ideas

The Sims 4 Bug Reports