Anna_Nikolash For the Serious Error message, please see the first post of this master thread:
[Current Issue] Sims 3 "serious error" when loading save | EA Forums - 8322938
Once you can load Sunset Valley, test the other worlds and let me know whether any of them are affected. The EA App may or may not have installed your DLC correctly. You can also try repairing the game in the App (Sims 3 > Manage > Repair), which would also repair the DLC.
You can ignore the error in the Sims 3 launcher.
I have no saves in sims 3 as its the first time I have opened it. I have tried to follow all steps you suggested, turned off One Drive, checked my documents files, unfortunately It did not help. I have also done all the steps below and zero change as well.
Step-by-Step Solutions 1. Clear EA App Cache and Restart Open the EA App. Go to Menu (☰) > Help > App Recovery > Clear Cache. Restart your computer and try installing the add-ons again. 2. Repair the Game and Add-Ons In the EA App, right-click The Sims 3 and select "Repair." Repeat for each expansion or stuff pack, if possible. 3. Manually Manage Installation Folders Close the EA App and ensure EABackgroundService is not running in Task Manager. Navigate to your Sims 3 install directory (typically C:\Program Files\EA Games\The Sims 3). Rename the current Sims 3 folder (e.g., Sims3-Old). Launch the EA App and reinstall The Sims 3. If add-ons still fail to install, copy the expansion/stuff pack folders (named EPxx or SPxx) from your old Sims 3 folder into the new one. This can prompt the EA App to verify and finalize the installation. 4. Check for Missing Add-On Shortcuts (Mac-specific) For Mac users, make sure each installed pack has an alias (shortcut) in the main Sims 3 Applications folder. If not, create an alias for each missing pack and place it in the correct folder as described in the workaround. 5. Addressing "Serious Error" When Loading Towns This error often indicates corrupted save files or missing/corrupted game data. Try starting a new game in a different town to see if the error persists. If the issue occurs with all towns, your installation may be incomplete or corrupted—reinstalling the game and add-ons as described above may help. 6. Script Errors in the Launcher Persistent script errors may be related to incomplete installations, leftover files, or mod conflicts. Remove any mods or custom content temporarily to rule out conflicts. If you use the NRaas ErrorTrap mod, check its logs for clues—sometimes, script errors point to missing or corrupted game objects. If script errors persist even with a clean install and no mods, the issue is likely with the EA App's handling of Sims 3 files. 7. Uninstall and Reinstall the EA App (Advanced) Uninstall the EA App completely. Use a registry cleaner (such as CCleaner or Revo Uninstaller) to remove leftover files. Restart your computer and reinstall the EA App. Reinstall The Sims 3 and add-ons.
