[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 ...

Given specific, non consistent, network connections, replication of some data can result in incorrect values

UE - Networking - Nov 2, 2016

I appears to be possible to replicate a value and when the value gets to the client(s), it doesn't match what was sent from the server. In the project, ReplicatedActor is created by the Authority. ...

Clicking the Add Variable button in a Struct that is referenced as two inputs in a function that is called in an Actor Blueprint's Construction Script causes a crash

UE - Gameplay - Blueprint - Jun 28, 2015

Clicking the Add Variable button in a Struct that is referenced as two inputs in a function that is called in an Actor Blueprint's Construction Script causes a crash. This does not occur in the Even ...

[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 ...

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 ...

Crash on garbage collection - Encountered 20 object(s) breaking GC Clusters assumptions.

UE - Foundation - Core - Aug 15, 2018

Garbage collection crash during opening cinematic. Note after crashing and relaunching the game the saved file appears as 8% complete instead of 0%. Note this crash is also occurring with //UE4/D ...

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): ...