The Sims 4's September patch drops on September 22nd, 2026 at 10AM PT / 7PM CET / 6PM BT, and it is a big one. Sims Community reports the update includes over 95 bug fixes, 10 crash and stability improvements, a wave of autonomy corrections, and relationship tuning for both Lovestruck and Growing Together. If you play with mods or maintain long-running saves, now is the time to back things up.
Here is what the patch addresses and how to make sure your game comes through it cleanly.
What the September patch fixes
The headline changes target some of the most-reported annoyances on the EA Forums. Married Sims will no longer revert to "Partners" when you enter CAS through Plan Outfits or Custom Tattoo planning. Interactions getting stuck in the queue, especially around sleep and group chat priority, have been addressed. The post-WooHoo freeze caused by autonomous interactions queuing during the act should also be resolved.
On the autonomy side, several small but noticeable improvements are coming. Sims will now face each other during conversations instead of staring off into space. They will use the bathroom sink after using the toilet rather than wandering to the kitchen. Low-energy Sims will stop randomly waking up to perform unrelated tasks. And if your Sim dislikes dancing, they will finally stop doing it on their own.
Lovestruck gets tuning adjustments: romantic satisfaction now decays more slowly, and relationship satisfaction no longer changes for inactive households. Growing Together's Family Dynamics see a rebalance too. Sims with bad compatibility and Distant or Difficult dynamics will now avoid each other more realistically, keeping conversations short or skipping them entirely. The "Compliant" and "Jokesters" dynamics both have reduced frequency, while "Distant" can now trigger after fights or malicious interactions.
The Laundry List post from September 15th also mentions that ten of the most common automated crash reports were traced and fixed, with the top crash stemming from conflicts with outdated mod files. Some issues remain under investigation, including broader Sim freezing bugs that the team described as "a '6 raccoons in a trench coat' sort of thing" and controllers occasionally stopping on console.
Looking further ahead, the October base game update will focus on food, dining, and drink improvements.
Back up your saves before Tuesday
If you play long-term legacy saves, challenges, or any file you care about, copy your save folder before the update lands. The file paths are:
- Windows:
C:\Users\[USERNAME]\Documents\Electronic Arts\The Sims 4\saves - Mac:
Macintosh HD/Users/User/Documents/Electronic Arts/The Sims 4/saves
Copy everything in that folder to a separate location: a desktop folder, a USB drive, or a cloud service. Label the backup folder with the date so you can find it later. If you need to roll back, you just paste the files back into the saves directory.
You should also back up your tray folder (same parent directory, folder named tray), which holds everything saved to your in-game library.
Do not load a save you care about after the update until you have confirmed your mods are working. A broken mod active in a save can cause corruption that a backup cannot always undo.
Handling mods and custom content
The Sims Team confirmed on Discord that this update is expected to impact mods. Their recommendation: back up saves and manage mods and CC carefully.
UI mods and gameplay/script mods are the most likely to break. The usual suspects, UI Cheats, More Columns in CAS, and any interface-replacement mods, tend to need updates first. Gameplay mods that include .ts4script files alongside their .package files should be removed or tested separately before you return to an existing save.
Pure custom content (hairs, clothing, furniture) rarely breaks, but it is not immune. If something goes wrong and you are not sure which file is the problem, the 50/50 method is the standard approach:
- Split your mods folder in half.
- Test each half separately.
- Whichever half contains the problem gets split again.
- Repeat until you isolate the broken file.
It is tedious with a large folder, but it works. Sims Community has a detailed 50/50 walkthrough from ThatSimsLady if you have not done it before.
A few things to keep in mind: script mods can only be one subfolder deep inside the Mods directory. Always delete the localthumbcache.package file before testing, as it regenerates on launch. And test against a fresh save first to avoid risking your main files.
Free content may tag along
Back in August, the Sims team teased a wave of free CAS and build/buy items, including size-inclusive clothing, a sculpted afro-textured hairstyle, new children's CAS content, and a variety of build items like fish tanks, bedroom furniture, and clutter. Some of that content shipped earlier, and remaining items could arrive with this patch or in a later drop. Nothing has been confirmed for September 22 specifically, but it is worth watching the patch notes when they go live.
We covered the full breakdown of the September 22 patch details earlier if you want the complete list of confirmed fixes.
Source: Sims Community via Google News - The Sims