Neighboring Houses show as Default/Empty

After reaching a corrupted state yesterday and quitting without saving, I today was able to reproduce it again, and this time saved just before, and then again during corruption with a "save as" copy. Happy to share my save files with the devs. I reproduced it again also without mods, on PC.

This issue is without having any residential rentals in my save, and it did not matter what family I loaded or if I went into just build mode from managed worlds into the neighbourhoods, they were always showing default buildings, once I had reached a certain amount of heavier buildings in my save (nothing crazy but nice gallery builds that have a low-medium amount of decoration). It also did not matter which buildings I placed, i reproduced it with totally different ones again and in different neighbourhoods. It seems like a max limit of objects within a save file to me.

Learnings:

1. It seems like replacing some simple builds with heavier builds was enough to reach the max limit that seems to corrupt the save file, as I had the same amount of builds in the save before and after reaching corruption ( = all lots built out in all existing worlds of all packs there are up until and including Adventure Awaits)
2. I did not have any residential rentals in my save, it seems to be just a max amount of objects, which may be amplified with residential rental use, but is not required to achieve it
3. When I placed my last bigger build that pushed me over the limit, I was seeing ALL neighbourhoods with default buildings, except the building i was loading into. I could test this even just in build mode from manage worlds, so the testing doesnt require loading into Willow Creek as I thought before, it will be broken everywhere I load into build mode.
4. Deleting some builds made the neighbourhoods go back to normal again after they had already corrupted, which is one more indication that there is a max limit
5. I wonder if the similar issue, that adjacent apartments are becoming completely empty when loading into an apartment is related, it seems like a similar problem, but I had this before reaching this full corruption state.

=> This sadly leads to the terminal fact that I can't buy any DLC with worlds anymore, as that will push my beloved save over the limit. It also makes me realise that starting from zero again will ultimately end up in the same result, so there seems to be no way out of this issue :( 

I really hope the devs can fix this, as this is the only game I play and the only save file I played since 2020, I'm so sad :(

• Mac
• Yes
• I had no residential rentals in my save. I never saved after a last exception. Several old clean saves wouldn't load correctly after the new Adventure Awaits pack. The only thing that worked was disabling For Rent. 

So far so good with fixing the default lots issue by following the advice on this link below.

https://simscommunity.info/2025/08/22/the-sims-4-memory-boost-mode/?fbclid=IwY2xjawMWUKJleHRuA2FlbQIxMABicmlkETFDeTlES1Vmamk0a0R4VDdPAR46Hio4PfDsXAdkuGntnpSFzNwztUvgrvTS4lAUz7_HMS5U7_mtmaw7oQEOOQ_aem_IYPGgLAZnsCEMl4eu0IhsA#discoveries-from-our-readers

Still in early testing but i have every expansion pack and use mods and adding lots in every world has so far not caused any issues... Still testing though...

Edit: Noticed that when attempting to visit a corrupted lot with a household sim the game will get stuck at the loading screen or crash to desktop. For the most part Willow Creek lots are still a write-off.

fortunately I was able to recover a previous save before the corruption happened. the corruption happened when I placed a sims household into a residential rental. I tried this quite a few times with the corruption reoccurring every time, until I deleted two empty residential rentals in another world, then I was able to place the sims in the rental with no issue.

I just had this happen to me for a second time, the last time this happened was in a different save file over a year ago. I noticed that one of the first big identifiers that my save is corrupting along with default lots is not being able to go to the second level in world view of a residential rental.

I don't know if this is related or not. But I wanted to add my 2 cents here if it's helping the devs with some problem solving. My game starts to stutter whenever the disappearing neighbouring builds/lots bug occurs.
I have a save game I curate for at least 5 years now with many new households and all lots replaced by new ones from the gallery and from other downloads as I am no builder. The first thing I do, when I get my hands on a new pack is to change the builds on those new lots. And as I know about those save corruption bugs, I always keep my eyes sharply on possible hints in the worlds.

One of those hints I noticed is when I am hopping from one lot to another to change the build, is when the game starts stuttering non stop. I then always exit the game without saving as this is the point when my neighbouring lots start to dissappear. I don't know why that is. I just go into a lot, change the build, save and go to the next one. For like 2 - 3 builds it works and then the game starts stuttering. I checked two times when this began what happens in the world and I let a sim of mine travel through different lots and the disappearances occur. I then roll back the save and check those lots again and everything is fine.

I found the file and added the extension and the issue is fixed! thank you :)

...Origin Games\The Sims 4\Game\Bin do you have here TS4_x64_fpb.exe or Simulation_x64_fpb.dll ?

hi, can you explain the second fix more for me? what is fpb.exe? It's not in my game install folder.

I already tried that but every time it shows up the same.