@imjuliewaters, I;m not sure. The only thing I can think of is that there was a glitch or some corrupted data in that save and not the others. One way to help get rid of leftover corrupted bits is to delete your local thumb cache package.file ! (It will be called localthumbcachepackage.file) . This should be done regularly, especially if you use Mods/CC!
For future reference, I will give you the list of steps that is best to take when trying to find if your CC or Mods are the cause of your problems , as well as which ones. I never heard of renaming your Mods folder like you did, but it seems to have worked! Usually people just move it to their desktop until they have found and replaced all outdated Mods and CC, at which point they can move it back where it normally belongs.
In the future, please do all of the following in order:
1) Move the Mods Folder to your desktop
2) Delete the localthumbcache.package file in the game folder. (This is very important!) 🤨
3) Fix you game in Origin by logging in and go to Library, then right-click on The Sims 4 and choose the "Repair Game" option from the list. Wait until Origin finishes repairing all your packs and not just the base game.
4) Now, when you turn on your game again, it will create a new mods folder that will be empty. Check to see if your game is now working without mods/CC.
5) Now you can try adding back items from your Mods folder one at a time checking your game each time to see which item is causing your game to not work properly. If you have a lot of items, you can try the 50/50 Method.
The CC creators will usually update the CC items and Mods after these updates, so when you find out which one is the culprit, you can get the updated version from whoever made that item of CC in the first place. You should try these steps any time you have problems in your game to rule out CC/Mods problems. It is the responsibility of the Mods/CC creators to update their items anytime EA releases a patch/update, and it is the responsibility of the people who use Mods/CC to make sure they are using the most recent version!
It is best to always try this when you have a problem. That way we can not only clear your localthumbcache, but also either fix your outdated Mods/CC or else rule them out as the cause of your problem! 🙂 That way, if your CC/Mods are ruled out as the culprit, we know that this might be a bug and you can file a Bug Report. 😉