Dangling pointer + mem corruption related to OwnerLastRenderTimePtr

UE - World Creation - Worldbuilding Tools - Mar 16, 2026

We've been seeing asserts and crashes related to OwnerLastRenderTimePtr. We've traced this to the mentioned pointer ending up dangling after using UActorComponent::Rename() on primitive components t ...

Graphical Artifacts in Editor with Macs using Certain AMD Graphics Cards

UE - Graphics Features - Sep 17, 2015

Users are reporting black and splotchy like graphical issues in their projects when working on a Mac and using an AMD graphics card. The user in the link provided mentions, "that UE 4.8.3 is withou ...

[CrashReport] UE4Editor_Engine!FPhysScene::SyncComponentsToBodies_AssumesLocked() [physscene.cpp:1271]

UE - Simulation - Physics - Dec 1, 2017

This is a common crash in 4.18 and 4.18.1. The callstack shares similarities to [Link Removed], although that has been confirmed fixed in 4.18. Included in the same crashGroup are also a few Ensur ...

Crash when enabling dynamic branch on static switches in Post Process Materials

UE - Rendering - Architecture - Materials - Jun 28, 2023

[Link Removed] Some functions to access parameters don't take into account the newly added runtime static switch parameters. It should be straightforward to fix these up: void UMaterialInstance:: ...

Niagara - When Interpolated Spawning is disabled, the first frame of each particle unexpectedly does not take into account the Particle Update stage

UE - Niagara - Feb 28, 2025

Foreword: Even if the behavior described here is by design, it is rarely (if ever) expected or desired. This was discussed and agreed to be treated as a bug. Explanation below. When interpolated sp ...

In 5.6, bWarningsAsErrors does not work with clang

UE - Foundation - Cpp Tools - UnrealBuildTool - Sep 20, 2025

In 5.6, many warnings and errors specify their command line arguments to the compiler with these new C# attributes:    [WarningsClangToolChain(["-Wno-date-time"], ["-Wdate-time", "-Wno-error=date-ti ...

Instanced Actors: PCG on RuntimeGrid "None" assigns created IAManagers RuntimeGrid "MainGrid", causing cross-grid reference

UE - World Creation - Procedural Tools - PCG Graph - May 30, 2026

Context PCG can be used to spawn Instanced Actors via the PCG IA Interop plugin, that makes Spawned Instanced Actors available as node. When a PCGActor placed in the level runs a PCG graph that spa ...

Material expression If node has been broken, major regression that shipped in 4.6

UE - Graphics Features - Dec 9, 2014

This sounds legit. Anyone mess with the if node recently? There seems to be a regression where existing content is broken. This should be fixed ASAP and patched into 4.6. https://forums.unrealen ...

Attempting to Open a Widget Blueprint With Animation and Timeline Panels Hidden Causes the Editor to Crash

UE - Editor - UI Systems - Nov 11, 2015

When you attempt to open a widget blueprint when you have hidden the animation and timeline panels, the editor will crash. There is a workaround: Window->Reset Layout will allow you to open the blu ...

MaterialTextureScale calculated incorrectly for materials with WorldPositionOffset

UE - Rendering - Architecture - Materials - Apr 16, 2024

When a Material uses WorldPositionOffset, the MaterialTextureScale is calculated incorrectly because FMaterialUtilities::ExportMaterialUVDensities() calls FMeshRenderer::RenderMaterialTexCoordScales ...