Save Game Corruption - Testing and Findings From 10 Years of Experience

Hi all!

I’m not sure if this is the right place to create this topic, but here we go.
I’m Davi, also known as ceunon20 on the forum, and I decided to open this discussion about Save Corruption because of my long and close experience with this “bug.”

So, I created a topic about this on the former EA Answers, but unfortunately, I never got any solutions at the time. I believe that was because I was the first—and probably the only—person experiencing this issue back then.
I’m not sure where that topic went, but you can get an idea from this other thread from 2017, where I left a comment about having the same problem with Magnolia Promenade: Error code: 800 | EA Forums - 11728790

Time went by, and I created new save files. I played a lot of The Sims 4, both with and without mods (I don’t use CC), and fortunately I never faced this bug again.

That is, until the release of For Rent…

When I first loaded For Rent on an active save file, Willow Creek was immediately affected by all the classic symptoms of save corruption, and my game became unplayable.
It was a 3–4 year-old save file that I unfortunately lost and could never recover.

After that, I decided to take some time off from TS4 and only came back with the release of the Business and Hobbies expansion pack.
And guess what I did? I started a brand-new save file from scratch—no mods, no CC.

I built everything myself: every lot in the game, Sims, clubs, and businesses. At first, everything went smoothly. My gameplay style leans heavily on progression—I like to play across multiple families for generations, updating their houses, relationships, and so on.

But once I actually started playing… Willow Creek once again began to disappear, little by little.

Fortunately, I had a backup save from before I started playing, and I noticed three things that I’ve also mentioned here [PLEASE READ] Save Game Corruption | EA Forums - 5037272
1 - Save file size
2 - Items limit
3 - Lots limit (for rent related)

What’s the goal here?
The idea is to create a topic where people can actively reproduce this bug, test it, and share their findings.

The Save Game Corruption thread is great, but it’s mostly filled with reports of the issue rather than actual testing. Since I’ve dealt with this problem for years—and that thread has gotten a bit overcrowded—I decided to open my own specifically for this purpose.

Here, I’ll share the method I use to reproduce the bug, based on my experience and years of observing how this corruption happens. That way, we can all test, discuss, and hopefully help The Sims Team work toward a solution.

HOW I BUILD A CORRUPTED SAVE GAME:

First of all—no one corrupts a save file on purpose. It just happens, and for many different reasons (you can find plenty of them in the Save Game Corruption thread).
What I can share, though, is the way I usually set up my save files—the same ones that eventually end up corrupted. To do that, we first need to prepare a few things so we’re ready when the corruption strikes.

1 - Put lots and Sims in Willow Creek

As I mentioned, we need to do a little setup before actually building the save file.

- Replace all the base game buildings in Willow Creek with new ones. Every single lot needs to be replaced.
- It can be your own buildings or just downloaded from the gallery 
- Any type of building is allowed but try to diversify as much as you can. Don't fill the world with just residential lots
- NO CC OR MOD IS ALLOWED
- You can use debug items
- You can use cheats like Move objects 

After that you can start populating the world as you like.
My advice is: don’t put too much effort into Willow Creek, since it will serve as our control world. The corruption always begins there. To avoid the frustration of losing a lot of progress, keep it simple but functional.

On the picture above, I marked the neighborhoods to show the order in which the corruption starts spreading.
It always begins in Foundry Cove and ends in Crawdad Quarter.
During the process, the lots in Foundry Cove, Courtyard Lane, Pendula View, and Sage Estates all disappear at once. But Crawdad Quarter behaves differently.
There’s something strange about Crawdad Quarter: when it gets corrupted, it happens gradually. You can literally see the lots deteriorating one by one until there’s nothing left. It always goes from Archives to Municipal Muses.

For some reason, Magnolia Blossom Park never gets corrupted. It’s the only lot in Willow Creek that survives intact—something I never really understood.

With all of this in mind, you can now begin the observation process, always starting in Foundry Cove, since it’s the first neighborhood to get fried.

How can I detect the corruption?
- Enter the lot and try to play with a Sim inside.
- Remember when I said you needed to replace all the lots? Here’s why: while playing with a Sim on the lot, check if the surrounding buildings are still the ones you replaced or if they reverted back to the base game versions. If they reverted, then your save file is officially corrupted.
- You need to perform this check every time you finish building a world. It’s mandatory for proper observation!

Now your game is set up to start the corruption.

2 - Building the worlds

From this point on, you can basically build the rest of the worlds however you like.
My advice here is: go all in.

But there’s one very important rule to follow: You need to build starting from the most recently released world and move backward to the earliest ones.

Why?
Over the years, I noticed that corruption always begins in Willow Creek and then spreads to Newcrest, Magnolia Promenade, Oasis Springs, and so on. Since Willow Creek is our control world, there’s no point in wasting too much time building in worlds that are likely to vanish once corruption spreads.

So, follow this order: Innisgreen → Nordhaven → Ravenwood → etc.

I tend to build my worlds going in a certain order as well:
1 - Lots
2 - Sims
3 - Relationships and drama
4 - Businesses
5 - Clubs

LOTS
- Try do diversify the lot types 
- Have at least 1 rental on each world (with at least 2 rental units)
- Try to do half residential/community. It's ok if not
- At least 1 unhabited lot on each world
- Try to edit the hidden worlds as well

SIMS
- Have at least 1 family with an animal on each world
- All ages are welcome
- Try to custom them as much as you can 
- Some supernaturals are a must

RELATIONSHIPS AND DRAMA
- Set relationships between Sims
- Give them jobs and professions
- Enable all the story progression (but don't allow them to move)
- Unlimited population
- All expansion pack features ON (seasons, ailments, fame, etc)

BUSINESSES
- At least 1 on each world
- You can make home businesses or off lot businesses

CLUBS
- At least 1 on each world (or more)
- Try to not repeat the activities on each club
- Don't put the same Sim on 2 or more clubs 

What’s next?
After finishing each world, go back and observe Willow Creek.
Finished Innisgreen? Check Willow Creek.
Finished Nordhaven? Check Willow Creek.

Once your save file is done, it’s time to actually play—while keeping a close eye on Willow Creek and Newcrest. Try not to play too much in these two neighborhoods, since they’re the first to show corruption signs.

This is basically the routine I follow when creating a save file and dealing with corruption.

Test with all the packs you own, and don’t forget to mention which ones you used when creating your save. That way, we can compare results and see which combinations still reproduce the bug (if not all of them).

I’ll be starting a brand-new save file myself so I can share my process with you all.

What do you guys think?
Any suggestions or other methods that we could try?