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 ...

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] UE4Editor-MetalShaderFormat.dylib!FGenerateMetalVisitor::print_constant()

UE - Graphics Features - Sep 22, 2017

This is an early trending crash coming out of the 4.18 previews. It occurs on Mac, and all affected project names indicate it is related to AR. Users have not provided any descriptions of their ac ...

Null FPhysicsActorHandle dereference in FBodyInstance::InitDynamicProperties_AssumesLocked when CreateShapes_AssumesLocked fails during async body init

UE - Runtime - Simulation - Aug 2, 2026

Summary When CreateShapes_AssumesLocked fails during async body creation, the failed FBodyInstance is left in Bodies[] with a released actor handle. InitDynamicProperties_AssumesLocked is then called ...

Physics Constraints do not have the same values if they are part of an 'Always Loaded' level

UE - Gameplay - Dec 3, 2014

Physics Constraints do not have the same values if they are part of an 'Always Loaded' level. They will work correctly in the Persistent level and a level that is Streamed in. This becomes problem ...

Assets containing TSet or TMaps fail to Nativize

UE - Gameplay - Blueprint Runtime - Dec 12, 2016

Multiple compile failures while attempting to nativize the QABP_Containers asset in QAGame. Errors:[2016.12.12-15.20.04:831][486]UATHelper: Packaging (Windows (64-bit)): xgConsole: QABP_Containers_ ...

[CRASH]SIGSEGV: invalid attempt to access memory at address 0x0

Tools - Jan 7, 2015

Callstack: <CALLSTACK START> FTaskThread::ProcessTasksUntilQuit(int) Address = 0x1091943e5 (filename not found) [in UE4Editor-Core.dylib] RenderingThreadMain(FEvent*) Address = 0x10de37e4b (filena ...

Constant Crashes on OS X 10.10.1

UE - Platform - Apple - Dec 15, 2014

User (Omri) on Mac running OS X 10.10.1. on MacBook Pro (17-inch, Early 2009 Experiencing Crash. Cannot reproduce. Crash Reporter: N/A Callstack: MachineId:1E07B9CE2F4554A7C3F421A9DD97AFB5 EpicAc ...

StateTree: While editing State Parameters or exposed properties of a Condition/Task, an ensure() fires when editing inputs of a Property Function bound to an array element

UE - AI - StateTree - Mar 5, 2026

Consider an array property that can be edited in the StateTree editor. This can be a State Parameter or an exposed property of a Condition or Task, for example. Each element of the array can be boun ...

Crash when a StateTree-related Parameter is of a type that includes two nested arrays with the same name (due to FPropertyChangedEvent::ArrayIndicesPerObject using array names to map to their changed indices)

UE - Framework - Dec 19, 2025

This issue was reported in the context of adding and setting parameters on StateTrees, Tasks and related assets, but its root cause lies in the structure FPropertyChangedEvent and can possibly affec ...