In these save files are your sims living in the new world Henford-on-Bagley or have they visited any lots in this new world? Some players are reporting bloated save files with game-breaking lag and tons of blank empty households being generated after living in this world.
I noticed any save file that touches the new world breaks due to these issues. I spent days removing any mods without recent updates, updating the mods I could, (made sure to clear cache every time), and even started a clean game folder with no mods. It never helped. The two AHQ threads I was following on this issue are being looked into now... you'll notice a post from a Sims team member directly under the OP.
Link to combined threadsIf this is your problem then the best you can do is hit
Me too but the good news is EA is aware of this issue. It helps to make 100% your mods are not the issue because not everyone is experiencing this. The Cottage Living patch broke a lot of mods. How I've been playing is avoiding that world altogether. My sims do not live there and they do not visit. As long as I do that then the save file is fine but Henford-on-Bagley dooms any save file it touches beyond repair.