[CrashReport] Assertion failed: !Export.ClassIndex.IsNull() | UPackage::Save()

UE - Foundation - Core - Cooker - Sep 20, 2017

This is a somewhat common crash coming out of the 4.17 release. User Descriptionsclicked Launch->Firefox. This is the same project with in-game video-screens which has been crashing on Launch for W ...

Blueprint with Niagara System and Skeletal Mesh Components Automatically Updates Niagara System Skeletal Mesh

UE - Niagara - Apr 4, 2019

When adding a niagara system that reproduces a skeletal mesh and a skeletal mesh as components to a blueprint, the niagara system immediately updates its skeletal mesh to the most recently updated s ...

Crash when resizing window using Quad Stereo Buffer

UE - Virtual Production - nDisplay - Oct 2, 2019

We noticed crashes in our application when we attempted to resize a window or switch to full-screen mode. Hence, resizing windows and switching to full screen will result in a crash on Unreal Engine ...

InlineEditConditionToggle behavior present for UProperties even when InlineEditConditionToggle property specifier is not used

UE - Editor - Workflow Systems - Jun 6, 2024

Reported by customer: It seems like in some cases, even when the InlineEditConditionToggle property specifier is not used, the behavior it enables is turned on anyway. It's possible to disable it w ...

Body Setup of a Static Mesh with Simple Collision will pass validation, but removing it and using only a Complex collision and setting Collision Complexity "Use Complex as Simple" will fail validation: "Bone None requires at least one collision shape".

UE - Simulation - Gameplay - Oct 20, 2025

Context: By default, Unreal Engine creates both simple and complex shapes, then, based on what the user wants (complex query versus simple query), the physics solver will use the corresponding shape ...

Reparenting a non-widget BP A to UUserWidget then reparenting a widget BP B to A causes an assert when compiled

UE - Gameplay - Blueprint Editor - Apr 12, 2018

No user comments in crash group ...

Adjusting color picker value for color structs within a structure crashes editor

UE - Gameplay - Blueprint - Aug 1, 2016

Attempting to adjust the value of a color struct via the color picker in structures crashes the editor. Frequency: 3/3 CrashReporter: [Link Removed] Regression (Yes) issue (does not) occur in 4. ...

Setting color in linear color struct variable within another struct crashes the editor

UE - Gameplay - Blueprint - Jun 16, 2016

Setting color in linear color struct variable within another struct crashes the editor. Frequency: 4/4 Regression (yes) issue (does not) occur in 4.11.2 ...

Creating a Blueprintable Struct that contains a Tmap results in Editor Crash

Tools - Sep 6, 2019

Any blueprint with a TArray of a struct containing a TMap crashes the editor when adding elements ...

[CrashReport] UE4Editor_CoreUObject!UObjectBase::IsValidLowLevelFast() [uobjectbase.cpp:294]

UE - Gameplay - Blueprint - Aug 15, 2017

This is a trending crash coming out of the 4.17 release. Users have not provided useful descriptions of their actions when the crash occurred. User Descriptionschecking stuff on internet. what does ...