A new blog post has been shared on The Sims 4 official website. It talks about the state of the investigations concerning save file corruptions.

It also confirms a new Laundry List tomorrow, November 25th. Read it below.

Reticulating the Splines: An Update to our Quality of Life Roadmap

Here at The Sims, we love creating games that allow you to experiment with life.

The Sims 4 is our most ambitious life sim yet. It’s defined by limitless creativity; not just within the game itself, but how you choose to play, what platform you play it on, what you download from the Gallery, and whether you kit it out further with Custom Content or Mods. Every Sim, build, creation, and choice you make adds something unique to the experience. It also adds complexity.

While it’s true that making any game is hard, life simulation games are especially challenging due to their deep interconnectivity, free form gameplay, and the randomness built into the simulation engine itself. When you add in years of updates, there are more than 2.4 quintillion possible combinations (really!) of Expansion Packs that a player could own. If we spent one second testing each combination, it would take over 77 billion years to go through them all! That doesn’t include Game Packs, Stuff Packs, custom content, or the differences in PC, Mac, and console hardware.

Even if two players take the exact same steps in their game, the outcomes could differ dramatically. That’s part of what makes The Sims 4 so alive and fun to create, and what makes tracking down bugs and stability issues uniquely challenging.

Our team loves the challenge of making this game, and while we’re always excited to rise to the occasion, we know we’ve been slower than we’d like to fix the issues you care about.  Complexity is part of the magic, and challenge, of The Sims, and an important reason for why some issues take longer to resolve than you may expect.  Our job is to keep improving the experience, one update at a time, and we’re not going anywhere.

A Commitment to Consistency

Back in September, we introduced our Quality of Life Roadmap and made a commitment to regularly fixing top community-voted issues, working closer with Mod creators to provide more advance information and notice, and providing clearer visibility into our update schedule. We’re shifting from large, infrequent patches to a steady regular cadence of updates. This commitment started in September, and will continue for the foreseeable future. In November, we delivered our first major step forward: over 150 bug fixes addressing many of the top community-reported issues.

Our next update will be on December 2nd, bringing 40+ additional fixes and improvements of your most voted issues. Our Laundry List will be published November 25th and provide more details, as well as a preview of what we’re fixing in January.

Alongside these updates, we’ll also be regularly hosting Dev Q&As with our team to give you opportunities to ask questions directly and learn more about how we approach fixes, testing, and player reports. Join Discord for our next Q&A November 25th!

Deep Dive: Save File Corruption

Issues impacting saves has been a concern for some of you. We’ve been investigating this deeply since early 2025, and over the past few months, our team has been testing and analyzing every lead, from corrupted lots to infinite loading loops, to identify the root causes. Thanks to new internal tools and player-submitted saves, we’ve been able to confirm several consistent patterns.

Recent Progress

• We identified and resolved an issue causing infinite loading when converting Penthouses or Dorms into Residential Rentals, shipped with the November 4 Base Game update. This will work retroactively to restore any previously impacted saves.
• Fixes for Error Codes 109:4fe45107, 109:d7e16575, and 123:b378c837 are coming in our December update. These address the issues seen in the affected saves, though we’re continuing to monitor for new variants. Work is ongoing to resolve Error 801, which occurs when multiple processes compete during load.
• We’ve also begun addressing a potential “Protobuf Overflow”, where save or Lot data grows so large it exceeds storage limits, leading to missing or corrupted lots. Our Memory Boost feature appears to reduce this risk on some hardware, and we’ve launched a survey to collect information from anyone who has experienced missing or corrupted data.

We’re also testing:

• Overstuffed or cheat-heavy Lots, where complex or modded placements may cause save corruption when cheats aren’t enabled.
• Mod data persistence, where removed mods leave residual data that can carry through Gallery uploads.
• Venue data carryover, where settings from one save can unintentionally transfer into another within the same session.

Our conclusion so far? There’s no single cause leading to these issues, and if you like getting into the technical details, we shared a deeper update in the EA Forums. If you’re experiencing performance issues, we published guides on how to back up your saves and make changes to reduce the chance of issues arising.

Our Ongoing Promise

We know bugs and instability can be frustrating, especially when they impact your stories and saves. We’re working to make the process of fixing them more transparent, consistent, and sustainable.

The Sims 4 has always been about creativity, connection, and community. Your feedback, comments, and votes via the EA Forums are continuing to drive what we prioritize, and your creations inspire us every day.

We’ll keep updating you on what’s fixed, what’s in progress, and what’s still under investigation. Together, we’ll continue making The Sims 4 the best and deepest simulation game in the world, one update at a time.

—The Sims Team