How To Fix ‘Serialization Error Action Needed’ in Ready or Not

Troubleshooting "Serialization Error Action Needed" in Ready or Not

Ready or Not Serialization Error

Screenshot via The Escapist

The "Serialization Error Action Needed" error in Ready or Not, often accompanied by "Corrupt data found, please verify your installation," is a common Unreal Engine issue. Here's how to resolve it:

Verify Game Files: This is the first troubleshooting step. Ensure Steam isn't in offline mode. In your Steam library, right-click Ready or Not, select "Properties," then "Local Files," and finally "Verify Integrity of Game Files." Steam will automatically replace any corrupted or missing files. Retry launching the game; if successful, the issue is resolved.
Remove Mods: Outdated or incompatible mods, especially those not updated for Unreal Engine 5 (post-July 2024), frequently cause this error. To remove mods:
- Access your Ready or Not local files via Steam's "Browse Local Files" option.
- Navigate to ReadyorNot\Content\Paks.
- Delete the mod.io folder.
This will disable all mods. The game should now launch, but you'll need to reinstall compatible mods.
Reinstall Mods Selectively: Reinstall mods one at a time, checking each mod's update date on Nexus Mods, Mod.io, or your preferred mod source. Only install mods updated after July 2024 (when Ready or Not transitioned to UE5). After each installation, test the game. If the error reappears, the last installed mod is the culprit and should be removed. Incompatible mods will not function with the UE5 version.
Reinstall Ready or Not: As a last resort, completely uninstall and reinstall Ready or Not. While less likely, hard drive corruption could also be a factor. However, outdated mods are the most common cause of this error.

Ready or Not is available now on PC.