USkeletalMeshComponent::HandleExistingParallelClothSimulation() calling WaitUntilTaskCompletes can trigger arbitrary task that modifies currently iterated UWorld::ComponentsThatNeedPreEndOfFrameSync

UE - Rendering - Architecture - Feb 23, 2024

Context ActorComponents can schedule an end-of-frame update for themselves by calling UWorld::MarkActorComponentForNeededEndOfFrameUpdate. The UWorld will iterate all those actor components once pe ...

Physics Asset primitives are being created with the default Name as None instead of BoneName_PrimitiveType

UE - Editor - Content Pipeline - FBX - Oct 27, 2024

When creating Physics Assets, either by automatic creation upon import, creation from skeletal meshes already in the project, or when we press Generate All Bodies (bottom right of a opened Physics A ...

AutoSize triggers ensure on shortened Skel Anim Section moved past anim length

UE - Anim - Sequencer - May 26, 2026

In Sequencer, calling "Edit > Auto Size" on a UMovieSceneSkeletalAnimationSection triggers the LowerBound > UpperBound ensure in UMovieSceneSection::SetRange (MovieSceneSection.h:333) when the secti ...

Crash when using "Convert to Variable Curve"

OLD - Anim - Jun 7, 2016

Error message: Access violation - code c0000005 (first/second chance not available) Source Context: 7 8 DECLARE_CYCLE_STAT(TEXT("AnimSeq EvalCurveData"), STAT_AnimSeq_EvalCurv ...

[CrashReport] UE4Editor_Engine!FDistanceFieldAsyncQueue::Build()

UE - Graphics Features - Jul 24, 2017

This is a common crash callstack that has affected more than 300 unique users since at least the 4.11 release. Other Jiras in the past with similar callstacks include [Link Removed] and [Link Remo ...

Orientation Warping breaks incoming poses where bones are in component space

UE - Anim - Gameplay - Apr 17, 2025

The orientation warping node breaks incoming poses where bones are already in component space. This is because, in EvaluateSkeletalControl_AnyThread, we are repeatedly setting bone transforms direc ...

Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor

UE - World Creation - Worldbuilding Tools - World Partition - Dec 18, 2025

Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor. As described in the steps to reproduce, if we keep swapping bIsSpatiallyLoaded state and save a Streaming Level ...

Changing the ComponentClass of a ACharacter twice and trying to set a SkeletalMeshAsset crashes the engine

UE - Anim - Jan 22, 2026

Changing the ComponentClass of a ACharacter twice and trying to set a SkeletalMeshAsset crashes the engine with a "Cannot replace existing object of a different class" message. The conditions to re ...

Assert crash when playing Groom Cache with Card Mesh LOD

UE - Rendering - Graphics Features - May 29, 2026

Playing a Guides Groom Cache while Card Mesh LOD (Guide-Based) is active causes an assert in RunHairStrandsInterpolation_Cards when the renderer switches to Card LOD. Assert location:Plugins/Runtim ...

Crash due to D3D device being lost. (Error: 0x887A0006 - 'HUNG')

UE - Graphics Features - Feb 22, 2017

This JIRA has been made to consolidate all "D3D device being lost. (Error: 0x887A0006 - 'HUNG')" crashes into one. Previous Jira tickets include:[Link Removed][Link Removed][Link Removed][Link Remo ...