How to Fix Broken Mods

Broken mods are a normal part of playing The Sims 4 with custom content. A file can stop working after a game update, a script mod can become outdated, or two mods can conflict with each other. Sometimes the problem is small, like a missing thumbnail. Other times the game may crash, freeze, or refuse to load.

The good news is that most mod problems can be fixed without reinstalling the whole game. You just need to test your Mods folder carefully and remove the file that causes the issue.

Common Signs of Broken Mods

A mod or CC file may be broken if you notice strange behavior after adding new files or after updating the game.

Common signs include:

• The game crashes during startup.
• The game loads forever or freezes on the loading screen.
• CAS items appear with broken textures.
• Hair, clothes, or objects look red, white, shiny, or invisible.
• Build/Buy objects disappear or show missing parts.
• Menus, buttons, or interactions stop working.
• Sims ignore commands or reset often.
• The game creates lastException files.
• The problem disappears when the Mods folder is removed.

Step 1 - Back Up Your Saves

Before you start testing mods, make a backup of your saves. This is especially important if the game is crashing or if you use large gameplay mods.

Your saves are located in Documents/Electronic Arts/The Sims 4/Saves.

Copy the Saves folder to your desktop, external drive, or another safe place. You do not need to do anything complicated. Just keep a copy before removing or testing files.

Step 2 - Close the Game Completely

Never move, delete, or replace mod files while The Sims 4 is open. Close the game first. If the EA app is still running in the background, it is also better to close it before changing many files.

This helps avoid file errors and makes sure the game reloads your Mods folder properly the next time you start it.

Step 3 - Delete localthumbcache.package

After changing mods or custom content, delete the localthumbcache.package file from the main Sims 4 folder.

You can find it here: Documents/Electronic Arts/The Sims 4/localthumbcache.package.

This file stores cached data. If it keeps old information from a broken or removed mod, the game may still show problems even after you delete the bad file. The game will create a new cache file automatically when you open it again.

Step 4 - Test the Game Without Mods

Move your entire Mods folder to the desktop. Do not delete it. Just move it out of The Sims 4 folder for testing.

Then start the game and check if the issue is gone. If the game works normally without the Mods folder, then the problem is almost certainly inside your mods or custom content.

If the game still has the same problem without mods, the issue may be related to the game itself, a save file, settings, or a recent update.

Step 5 - Check Recently Added Files First

If the problem started after you installed new files, check those files first. This is often the fastest way to find the cause.

Open your Mods folder and sort files by date. Move the newest files out of the folder, delete localthumbcache.package, and test the game again.

If the game works after removing the newest files, one of them was likely the problem.

Step 6 - Use the 50/50 Method

If you do not know which file is broken, use the 50/50 method. This is one of the best ways to find bad mods when your Mods folder is large.

1. Split your Mods folder into two parts.
2. Put one half back into the Mods folder.
3. Start the game and test the problem.
4. If the problem appears, the broken file is in that half.
5. If the problem does not appear, test the other half.
6. Keep splitting the problem group until you find the bad file.

This method can take time, but it is reliable. It is much better than guessing randomly when you have hundreds or thousands of files.

Step 7 - Check Script Mods After Updates

Script mods are more sensitive to game updates than regular custom content. If The Sims 4 was recently updated, check script mods first.

Script mods often use .ts4script files. They can add new systems, menus, settings, and gameplay features. Because they affect how the game works, they may break after a patch.

Visit the creator's page and check if the mod has a new version. If there is no update yet and the mod causes problems, remove it temporarily.

Step 8 - Look for Duplicate Mod Versions

Sometimes players accidentally keep two versions of the same mod in the Mods folder. This can happen when you update a mod but forget to remove the old files.

Duplicate versions can cause conflicts, missing menus, broken interactions, or random errors. Search your Mods folder for the mod name and make sure only the latest compatible version is installed.

Step 9 - Check for Missing Meshes

If hair, clothing, furniture, or decor looks broken, the problem may be a missing mesh. Some custom content is only a recolor or edit of another item. Without the original mesh, the CC may not display correctly.

Go back to the download page and check if the creator says that a mesh is required. If yes, download the required mesh and place it in your Mods folder.

Step 10 - Test With a New Save

If the game opens but one save file behaves strangely, test a new save. Create a temporary household and check if the same problem happens there.

If the problem appears only in one old save, that save may contain outdated mod data, broken objects, or a household affected by a removed mod.

What Are lastException Files?

A lastException file is an error report created by the game when something goes wrong. These files can appear in the main Sims 4 folder after a mod error or game error.

A lastException file does not always mean your game is ruined. It is a sign that something caused an error. If these files appear often after installing a specific mod, that mod may be outdated or conflicting with another file.

How to Prevent Broken Mods

You cannot prevent every broken mod, but you can make problems easier to fix.

• Do not install too many files at once.
• Keep script mods updated.
• Read the creator's instructions before installing.
• Organize your Mods folder by type.
• Remove old versions before adding updated versions.
• Back up your Saves folder before big updates.
• Delete localthumbcache.package after changing mods.

Should You Delete All Mods and Start Over?

You usually do not need to delete everything. If the game works without the Mods folder, the problem is probably one file or one small group of files. Use careful testing before removing your whole collection.

Starting over can help if your Mods folder is very old, messy, or full of unknown files. But in most cases, the 50/50 method is enough.

Final Notes

Broken mods can be annoying, but they are usually fixable. The most important thing is to stay calm and test step by step. Remove recent files, check script mods, delete the cache file, and use the 50/50 method if needed.

A clean Mods folder makes The Sims 4 easier to manage. Once you know how to find broken files, updates and mod problems become much less stressful.