Does anyone know how to fix the error "Assertion Failed: SerializeNum >= 0"?

Development Programming & Scripting
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1

I’ve been trying to work on my project and I keep getting this error whenever I try to enter anything that is not the default project map, that includes blueprints, other maps, and animations.

Full Error:
Assertion failed: SerializeNum >= 0 [File:D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Containers\Array.h] [Line: 3746]

UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_ContentBrowserAssetDataSource
UnrealEditor_ContentBrowserAssetDataSource
UnrealEditor_ContentBrowserAssetDataSource
UnrealEditor_ContentBrowserAssetDataSource
UnrealEditor_ContentBrowser
UnrealEditor_ContentBrowser
UnrealEditor_ContentBrowser
UnrealEditor_ContentBrowser
UnrealEditor_ContentBrowser
UnrealEditor_ContentBrowser
UnrealEditor_ContentBrowser
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
user32
user32
UnrealEditor_ApplicationCore
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
kernel32
ntdll

2

Hello there @WavierSole_1722!

That error has showed up in other threads accross the community, its usually tied to invalid or missing data. There are a few approaches to resolution:

  • Clear your project by deleting folders Saved, Intermediate, and DerivedDataCache
  • Check for any redirectors in your folders using “Fix Up Redirectors”
  • Re-validate your files by going to Tools > Asset Actions > Reload / Recompile All Blueprints
  • Move your assets to a clean project, to check if the issue persists there