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

Ready or Not, while sounding like a children's game, is anything but. This intense single and multiplayer SWAT FPS delivers a realistic experience, but occasionally, technical hiccups can occur. One such issue is the dreaded "Serialization Error Action Needed" message. Here's how to troubleshoot this problem.

The "Serialization Error Action Needed" error in Ready or Not, often accompanied by "Corrupt data found, please verify your installation," points to an Unreal Engine issue. Let's explore the solutions.

1. Verify Game Files

The game itself suggests the first step: verifying your installation. This checks for missing or corrupted files. Here's how (ensure Steam isn't in offline mode):

1. Open your Steam Library.
2. Right-click Ready or Not and select Properties.
3. Navigate to Local Files > Verify Integrity of Game Files.

Steam will automatically download any necessary files. Try launching the game again. If successful, you're all set. If not, proceed to the next steps.

2. Remove Mods

Outdated or incompatible mods, especially those not updated for Unreal Engine 5, are a common culprit. To remove mods:

1. Open your Steam Library and locate Ready or Not.
2. Click Manage > Browse Local Files.
3. Navigate to the ReadyorNot > Content > Paks folder.
4. Delete the mod.io folder.

This will resolve the error, but you'll lose your mods temporarily. Follow the next step to restore them selectively.

3. Reinstall Mods Selectively

Reinstall your mods one by one, checking their last update date on Nexus Mods, Mod.io, or your preferred modding platform. Mods updated after July 2024 (when Ready or Not transitioned to UE5) are more likely to be compatible. Install a mod, test the game, and repeat. If the error reappears, the last installed mod is the problem; skip it. Incompatible mods (those not updated for UE5) won't work.

Last Resort: Reinstall the Game

If all else fails, a complete uninstall and reinstall of Ready or Not might be necessary. While less likely, hard drive corruption could also be a factor. However, outdated mods are the most frequent cause of this error.

Ready or Not is available now for PC.