The Sims 4's next major patch drops on September 22, and it is a big one. With 95+ bug fixes, 10 crash and stability improvements, a batch of autonomy corrections, and relationship tuning for both Lovestruck and Growing Together, this update touches enough systems that preparing your saves and mods ahead of time is worth the effort.
Here is what the patch contains, how to back everything up, and how to deal with broken mods afterward.
What the September 22 patch actually fixes
The September 15 Laundry List from Sims Community breaks down the full scope. The highlights fall into a few buckets.
Autonomy improvements are the headliner. Sims will now face each other during conversations instead of staring into the void. They will use the bathroom sink after using the toilet rather than walking across the house to the kitchen. Low-energy Sims will stop waking up to perform random tasks. NPC couples from Lovestruck will no longer obsessively sky-gaze or make out in libraries. Sims who need to pee will walk faster during the urgent animation.
Interaction queue and freeze fixes target several overlapping bugs the dev team described as "a 6 raccoons in a trench coat sort of thing." Sims getting stuck in interaction queues, freezing after WooHoo when an autonomous action queued during the act, and time-freezing while the environment kept animating have all been addressed. The excessive autonomous dancing bug, where stereos spammed dance interactions, also gets multiple fixes, though that particular one only applies to new saves.
Relationship tuning gets attention across two expansion packs. For Lovestruck, Relationship Satisfaction will no longer change for inactive households, and romantic satisfaction decays more slowly. For Growing Together, Sims with awful compatibility and Difficult or Distant Family Dynamics will now rarely start conversations, actively avoid each other, and keep interactions short. The Compliant and Jokesters dynamics will trigger less often, while the Distant dynamic (which was barely appearing) now has a real chance to fire when Sims fight or run mean interactions.
Other notable fixes include married Sims no longer reverting to "Partners" when entering CAS through Custom Tattoo planning or Plan Outfits, infants no longer stacking on each other or popping out of cribs after reloading, and roof trim no longer clipping through platforms and half walls.
EA has also previewed that October's update will focus on food, dining, and drink improvements, including a tuning pass on calories and food pricing.
How to back up your saves before patching
If you play long-term saves, legacies, or challenges, backing up is straightforward and takes a few minutes.
Navigate to your saves folder:
- Windows:
C:\Users\[USERNAME]\Documents\Electronic Arts\The Sims 4\saves - Mac:
Macintosh HD/Users/User/Documents/Electronic Arts/The Sims 4/saves
Copy your save files to a separate location. A USB drive, external hard drive, or cloud folder all work. Name the backup folder with today's date so you know which version you are restoring if something goes wrong.
You can do the same with your tray folder, which holds everything saved to your in-game library:
- Windows:
C:\Users\[USERNAME]\Documents\Electronic Arts\The Sims 4\tray - Mac:
Macintosh HD/Users/User/Documents/Electronic Arts/The Sims 4/tray
To restore a save, copy it from the backup folder back into the Sims 4 saves directory.
Handling mods after the update
The Sims Team confirmed on Discord that this update will have an impact on mods and recommended backing up saves and managing mods and CC carefully.
UI mods and gameplay mods are the most likely to break. UI mods include UI Cheats, More Columns in CAS, and any user interface replacement mods. Gameplay mods, especially those with both .package and .ts4script files, should be removed and tested individually or only added back after the creator confirms compatibility.
The safest approach: do not load saves you care about until your mod creators have posted about the update status. Test in a fresh save file first, since some fixes in this patch may only apply to newer saves.
Always delete the localthumbcache.package file before launching after a mod change. It regenerates on startup and stale versions can cause issues.
The 50/50 method for finding broken mods
If your game crashes or behaves strangely after the patch, the 50/50 method is the standard way to isolate the problem file.
- Back up your entire Mods folder.
- Remove half of your mods, keeping only the other half active.
- Launch the game and test. If the issue persists, the problem is in the active half. If not, it is in the half you removed.
- Take the half that contains the issue and split it again.
- Repeat until you find the specific file causing the problem.
A few things to keep in mind: script mods can only be one subfolder deep inside the Mods directory, while custom content can go up to five folders deep. Mods that come with both a .package and .ts4script file must stay in the same folder. And mod dependencies like Lot51's Core File, the XML Injector, or Lumpinou's Mood Pack need to be present alongside any mods that require them.
Sims Community has a detailed walkthrough of the 50/50 method by ThatSimsLady if you want a more visual guide.
When the patch goes live
The September patch releases on September 22, 2026 at 10:00 AM PT / 7:00 PM CET / 6:00 PM BT across PC, Mac, Xbox, and PlayStation.
If you have been dealing with phone notification spam or other quality-of-life annoyances from earlier updates, this round of fixes should help. The autonomy and relationship changes alone touch some of the most persistent complaints in the community.
Source: Sims Community