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

Ready or Not, while sounding deceptively innocent, delivers a hardcore SWAT FPS experience—both solo and multiplayer. However, even seasoned operators can encounter technical glitches. This guide tackles the frustrating "Serialization Error Action Needed" issue in Ready or Not.

The "Serialization Error Action Needed" error, often accompanied by "Corrupt data found, please verify your installation," is a common Unreal Engine headache. Here's how to resolve it:

1. Verify Your Game Files

The game itself suggests the solution: verify your installation. Ensure Steam isn't in offline mode. Follow these steps:

1. Open your Steam Library and locate Ready or Not.
2. Right-click, select "Properties," then "Local Files," and finally "Verify Integrity of Game Files."
3. Steam will scan and replace any corrupted or missing files. Try launching Ready or Not again. If successful, problem solved! If not, proceed to the next step.

2. Remove Your Mods

Outdated or incompatible mods, especially those not updated for Unreal Engine 5, are a frequent culprit.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

1. In your Steam Library, locate Ready or Not.
2. Left-click "Manage," then "Browse Local Files."
3. Navigate to ReadyorNot\Content\Paks and delete the mod.io folder.

This will resolve the error, but you'll lose your mods temporarily. See step 3 for how to get them back.

3. Reinstall Mods (One by One)

Reinstall your mods carefully, one at a time. Visit Nexus Mods, Mod.io, or your mod source. Before reinstalling, check the last update date. 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 returns, the last installed mod is the problem; skip it. Unfortunately, pre-UE5 mods are likely unusable.

Last Resort: Reinstall the Game

If all else fails, a clean reinstall of Ready or Not might be necessary. While less likely, hard drive corruption could also be the cause. However, outdated mods are the most common reason for this error.

Ready or Not is available now for PC.