# Packaging failed due to Assertion Failed ClassData

**URL:** <https://forums.unrealengine.com/t/packaging-failed-due-to-assertion-failed-classdata/498525>\
**Category:** Platform & Builds\
**Tags:** UE4-24, assertion-failed, critical-error, Packaging-Error, unreal-engine\
**Created:** [February 16, 2022, 12:48am UTC](https://forums.unrealengine.com/t/packaging-failed-due-to-assertion-failed-classdata/498525 "2022-02-16T00:48:11Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Capn\_C4ke](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/capn_c4ke/32/1194596_2.png) [@Capn\_C4ke](https://forums.unrealengine.com/u/Capn_C4ke)\
**Post date:** [February 16, 2022, 12:48am UTC](https://forums.unrealengine.com/t/packaging-failed-due-to-assertion-failed-classdata/498525/1 "2022-02-16T00:48:11Z")

</div>

I’ve been trying to package my game but it keeps saying critical error. I was able to package it properly yesterday, and barely even touched anything today. I literally have no idea what’s going on, and I don’t have a recent backup to be able to revert to. What can I do??

UATHelper: Packaging (Windows (64-bit)): LogWindows: Error: === Critical error: ===  
UATHelper: Packaging (Windows (64-bit)): LogWindows: Error:  
UATHelper: Packaging (Windows (64-bit)): LogWindows: Error: Assertion failed: ClassData [File:D:/Build/++UE4/Sync/Engine/Source/Programs/UnrealHeaderTool/Private/CodeGenerator.cpp] [Line: 2665]  
UATHelper: Packaging (Windows (64-bit)): LogWindows: Error:  
UATHelper: Packaging (Windows (64-bit)): LogWindows: Error:  
UATHelper: Packaging (Windows (64-bit)): LogWindows: Error:  
UATHelper: Packaging (Windows (64-bit)): LogWindows: Error:  
PackagingResults: Error: === Critical error: ===  
PackagingResults: Error: Assertion failed: ClassData [File:D:/Build/++UE4/Sync/Engine/Source/Programs/UnrealHeaderTool/Private/CodeGenerator.cpp] [Line: 2665]