ChaosCacheManager is not reproducing Collision Events the second time you Record and Play

UE - Runtime - Simulation - Mar 28, 2025

ChaosCacheManager (CCM) is not reproducing Collision events the second time (and onwards) we record a Geometry Collection (GC) breaking session. Particles set to track Collision Events correctly fol ...

Crash When Typing a Node Comment and Hovering Over the Alignment Option

Tools - Apr 5, 2016

Error message: Assertion failed: ParentIndex != INDEX_NONE [Link Removed] [Line: 512] Source Context: 499 } 500 501 return Menu; 502 } 503 504 ...

Editor ensure in USceneComponent::OnComponentDestroyed during Blueprint compilation GC

UE - Framework - Components - Jan 15, 2026

An editor-only ensure can trigger during BP compilation when garbage collection cleans up transient components created as part of component replacement. During recompilation, old component instances ...

[CrashReport] ULevel::GetWorldSettings - UMaterialFunctionThumbnailRenderer::Draw

Tools - Oct 30, 2017

This is a common crash that has occurred since at least 4.16. The callstack is nearly identical to [Link Removed], which appears to be fixed in 4.18; and [Link Removed], which has not. The differen ...

Deadlock when running an asset validator commandlet with async skeletalmesh build

UE - Editor - Open File Formats - Asset Migration - Mar 10, 2023

[External Code]   UnrealEditor-Core.dll!FEventWin::Wait(unsigned int WaitTime, const bool bIgnoreThreadIdleStats) Line 1515 C++   UnrealEditor-Engine.dll!FAsyncTaskBase::WaitCompletionWithTimeout( ...

[CrashReport] Assertion failed: !bIsReentrant - UE4Editor-UnrealEd.dylib!SaveWorld()

UE - Platform - Apple - Jul 27, 2017

This is a common crash on Mac in 4.16 and has occurred since at least 4.14. User DescriptionsI added a character to a blank map and tried to save it. Callstack from LogLogEditorViewport: Clicking ...

Niagara Scalability Crash When Processing Significance

UE - Rendering - Architecture - Niagara - Jun 4, 2025

Method FNiagaraScalabilityManager::ProcessSignificance() iterates on indices from Context.SignificanceIndices and uses them to access the State and ManagedComponents arrays. It can then decide to cr ...

Crashes when attempting to use an Instanced Struct inside Control Rig / Rig VM

UE - ACT Character - Control Rig - Mar 17, 2025

Currently, the Control Rig Editor allows the user to use the "Instanced Struct" type, for example for a variable or function input/output. However, this type does not seem to be properly supported ( ...

MovieRender Pipeline Skips Output Frames during GC

UE - Anim - Sequencer - Jun 8, 2020

This is being seen in the wild... can release a temporary fix until 4.26 when we can change the headers and fix it for real. ...

FirstPerson template project crosshair has white background on Samsung S6 Edge

UE - Platform - Mobile - Dec 6, 2016

This is a regression from 4.13.2 Seen on a Galaxy6Edge_6714 OS: 5.0.2 This was not seen on a HuaweiP9Plus_9532 OS: 6.0 ...