[CrashReport] Assertion failed: TaskDataArray.Num() == Exporter->VolumetricLightmapTaskGuids.Num()

UE - Graphics Features - Lumen - Oct 2, 2017

This is a trending crash coming out of the 4.18 Previews. Users have not provided any descriptions of their actions when the crash occurred, but at least two of the affected projects are being creat ...

iOS Metal-based build crashes at launch with sub-levels.

Tools - May 16, 2016

Application crashes when deploying a game to iOS with Metal enabled. This has only been reproduced if a sub-level has been added to the starting level within the project. This seems to only happen ...

[CrashReport] UE4Editor_D3D11RHI!VerifyD3D11Result() [d3d11util.cpp:200]

UE - Editor - UI Systems - Slate - May 9, 2016

This Jira was created from CrashReports submitted by the public due to the high number of occurrences. Error message: Fatal error: [Link Removed] [Line: 200] SwapChain->ResizeBuffers(1,SizeX,SizeY ...

[CrashReport] UE4Editor_Renderer!FSceneRenderTargets::GetGBufferResourcesUniformBuffer() [scenerendertargets.h:408]

UE - Graphics Features - Jan 18, 2016

This Jira was created from CrashReports submitted by the public due to the high number of occurrences. Descriptions from users are provided below. Error message: Assertion failed: IsValidRef(GBuff ...

Crash after adding Virtual Bone, then Creating Asset

OLD - Anim - Jul 5, 2017

Occurs on? 4.16 - 3466753 - YES 4.17 - 3521650 - YES Error message: Assertion failed: RefBonePose.Num() == NumBones [Link Removed] [Line: 4400] Source Context:4387 ResetAnimation(); 4388 ...

Shipping build crash when unplugging then replugging Oculus HMD

UE - Platform - XR - Nov 9, 2016

Game crashes in shipping build when un-pluging the Oculus HMD, then plugging it back in. Confirmed in 4.13.2 from the launcher, did not repro via same steps in 4.14 preview 3 ...

Map placed actor binding to another actor's Event Dispatcher (multicast delegate) results in duplicate bindings after blueprint recompile

UE - Framework - Blueprint - Apr 17, 2025

Context Blueprint actors placed on the map can bind to another actor's event. If an ActorB has a reference to ActorA, it can bind to an event dispatcher in A by creating an event node in ActorB's e ...

Level Instance Property Override: Actor::Tags overridden pre-CS but clobbered by RerunConstructionScripts with no post-CS re-apply

UE - World Creation - Worldbuilding Tools - May 4, 2026

Summary When using the Level Instance Property Override system, overrides applied to `AActor::Tags` are silently lost for Blueprint actors whose Construction Script assigns or appends to `Tags`. The ...

Compile error during build stage when packaging for tvOS

UE - Platform - Mobile - Dec 9, 2016

Compile error packaging for tvOS: Does not affect iOSUATHelper: Packaging (tvOS): UnrealBuildTool: D:\Build\joseph.wysosky_Main\Engine\Source\Runtime\Core\Private\iOS\IOSAppDelegate.cpp(388,12): ...

[CrashReport] Mac crash - UE4Editor-Slate.dylib!SMenuAnchor::SetIsOpen()

UE - Platform - Apple - Sep 14, 2017

This is a common and longstanding Mac crash that has occurred since at least 4.11 and affected more than 40 users. Users have not provided any descriptions of their actions when the crash occurred ...