Many players encounter this error after game updates because of files left in the folder. Navigate to Documents > Electronic Arts > The Sims 4 . Find the folder named ConfigOverride .
Delete the localthumbcache.package file located in your main The Sims 4 folder.
If you are still stuck after all these steps, visit the official EA Answers HQ or the Sims After Dark Discord, and attach your lastException.txt file from Documents\Electronic Arts\The Sims 4 . Do not reinstall Windows for this error—it is almost never an OS issue, but a file permission or rogue process issue. Many players encounter this error after game updates
The "Unable to start: there was an error processing the startup configuration script" message (often accompanied by error code ) typically occurs when the game cannot read or process critical graphics and system rule files. This is often triggered by corrupted game files, outdated graphics drivers, or conflicts within the ConfigOverride folder. Immediate Troubleshooting Steps
If you recently updated your graphics drivers, Sims 4 might be trying to use an "exclusive" GPU command that your new driver rejects. The game keeps a GraphicsCards.sgr and GraphicsRules.sgr file. Delete the localthumbcache
Open your directory ( Documents > Electronic Arts > The Sims 4 ). Locate and delete the file named localthumbcache.package .
If OneDrive is syncing your Documents folder, it can "lock" files while the game tries to read them. Disable OneDrive syncing for the Electronic Arts folder. The "Unable to start: there was an error
Follow these troubleshooting steps to get your game back up and running. 1. Clear the ConfigOverride Folder (Common Fix)
Corrupted installation files can demand exclusive access to fix themselves, fail, and then block the game.
The word “exclusive” in the error often points to a script expecting a single instance (like a loading overlay) but finding another process interfering. This is almost always a mod conflict or antivirus locking the file . Step 1 and Step 5 solve ~95% of cases.
The error message " The Sims 4 is unable to start: There was an error processing the startup configuration script" often occurs when the game is blocked from accessing its user folder or when specific graphics configuration files are corrupted or misplaced. Primary Fix: Clear the ConfigOverride Folder