The Sims 4's next major patch lands on September 22, 2026 at 10 AM PT / 7 PM CET, and it is a big one. Over 95 bug fixes, 10 crash and stability improvements, autonomy corrections, and relationship tuning for multiple packs are all packed in. If you play with mods or long-term saves, the two days before launch are the time to back everything up.

Here is what the patch changes, what free content may tag along, and exactly how to protect your files.

What the September 22 patch actually fixes

The September Laundry List from the Sims team breaks the update into a few categories.

Autonomy corrections are the headline. Sims will now face each other during conversations instead of talking to walls. After using the toilet, they will walk to the bathroom sink rather than trekking to the kitchen. Low-energy Sims stay asleep instead of popping up at 2 AM to wash dishes. Sims who need to pee walk faster when their bladder is critically low. And Lovestruck couple walkbys will stop obsessively kissing at non-residential venues.

Bug fixes cover some long-standing frustrations. Married Sims reverting to "Partners" after using CAS through tattoo planning or outfit changes is resolved. Several freeze states are gone, including Sims getting stuck in interaction queues after sleep, chat, or WooHoo. Infants popping out of cribs and playmats on reload are fixed. Roof trim clipping near platforms and half walls is corrected. Stereos spamming autonomous dance interactions (which only affected newer saves) no longer happens, and Sims who dislike dancing will refuse to do it on their own.

Relationship tuning touches three packs. For Lovestruck, Relationship Satisfaction no longer shifts for inactive households, and romantic satisfaction decays more slowly over time. For Growing Together, Sims with terrible compatibility now rarely initiate socials, avoid each other, and keep conversations short. The Compliant and Jokesters dynamics trigger less often, while the Distant dynamic is easier to obtain through fights or malicious interactions. Enchanted by Nature also gets a tweak: Sims with bad luck experience fewer negative relationship impacts while socializing.

The Sims team has already signaled that October's base game update will shift focus toward food, dining, and drink improvements.

Free cosmetic content on the horizon

Back in August, the Sims team teased a round of free content drops including new clothing designed to flatter plus-sized Sims, a sculpted afro-textured star-themed hairstyle, and multiple build/buy mode items. Some of that content arrived in the first drop, but remaining items, including additional hairstyles, children's CAS content, a new fish tank, bedroom furniture, and assorted clutter, are still expected later this year. Whether any of it ships alongside the September 22 patch or arrives separately has not been confirmed.

How to back up your save files before the patch

If you play long-term saves like legacies, challenges, or forever saves, backing up before any major update is worth the few minutes it takes. Here is the process:

  1. 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
  1. Copy any save files you want to protect. Files are numbered, so sort by date modified to find recently played saves. If you are not sure which to grab, copy all of them.
  2. Paste them into a separate location: a folder on your desktop, a USB drive, an external hard drive, or a cloud service. Naming the backup folder with the current date helps you keep track.
  3. Do the same for your tray folder (same parent directory, subfolder called tray), which holds anything saved to your library through the Gallery.

To restore a save later, just copy it back into the main saves folder.

Preparing your mods folder

The Sims team confirmed on Discord that this update will have an impact on mods. Their recommendation: back up your saves and manage your mods and CC carefully.

The mods most likely to break are UI mods (UI Cheats, More Columns in CAS, any interface replacement) and gameplay mods, especially those containing .ts4script files. Custom content is usually fine, but it can still go wrong.

Before loading a save you care about after the patch, wait for mod creators to post compatibility updates. Test with a fresh save first to avoid corruption in your main files.

If something does break, the 50/50 method is the standard way to track down the culprit. Split your mods folder in half, test each half separately. Whichever half contains the problem gets split again, and you repeat until you isolate the broken file. It is tedious with a large folder, but it works.

A few details that trip people up:

  • Script mods can only be one subfolder deep inside the Mods folder. Custom content can go about five folders deep.
  • Never separate a mod's .package file from its .ts4script file. They need to stay together.
  • Mod dependencies (Lot51's Core File, XML Injector, Lumpinou's Mood Pack, etc.) must be tested alongside the mods that require them and may need their own updates.
  • Always delete the localthumbcache.package file before testing. It regenerates on launch and can cause false positives if it holds stale data.

If you have been meaning to organize your mods folder, now is a reasonable time to do it. Sorting by type (hairs, makeup, build items) or by creator both work, as long as the system makes sense to you and you can find things when something breaks.

When to expect the patch

The September 22 update rolls out simultaneously on PC, Mac, Xbox, and PlayStation at 10 AM PT / 7 PM CET / 6 PM BT. If you use mods, resist the urge to jump into your main save immediately. Give creators a day to test and update, and run the game vanilla or on a throwaway save first to confirm stability.

For more on what the Sims team has been fixing recently, we previously covered how you can finally silence your Sim's phone following the June 30 update.

Source: Sims Community via Google News - The Sims

Related SimGoodie reading