Troubleshooting "Serialization Error Action Needed" in Ready or Not

1. Verify Game Files

Begin by verifying your game files through Steam. Ensure Steam isn't in offline mode.

• Locate Ready or Not in your Steam Library.
• Right-click, select Properties, then Installed Files, and finally Verify Integrity of Game Files.

Steam will identify and redownload any corrupted or missing files. Retry launching the game; if successful, the issue is resolved. If not, proceed to the next steps.

2. Disable Mods

Outdated or incompatible mods, especially those not updated for Unreal Engine 5 (post-July 2024), frequently cause this error. To remove mods:

• Locate Ready or Not in your Steam Library.
• Left-click Manage, then Browse Local Files.
• Navigate to ReadyorNot\Content\Paks.
• Delete the mod.io folder.

This will allow the game to run without mods. To regain functionality, follow step 3.

3. Reinstall Mods (One by One)

Reinstall mods selectively, checking their last update date. Only install mods updated after July 2024 (the UE5 update).

• Visit the mod's source (Nexus Mods, Mod.io, etc.).
• Check the update date. Only install post-July 2024 mods.
• Install one mod, test the game. Repeat, installing one mod at a time.
• If the error returns, the last installed mod is the culprit; remove it.

4. Reinstall Ready or Not (Last Resort)

If all else fails, a clean 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 However, outdated mods are the most common cause of this error.

Ready or Not is available on PC.