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 ...

Crash saving a destructible mesh after creating it from static mesh

UE - Simulation - Physics - Destruction - Sep 29, 2016

Crash occurs when saving a destructible mesh after creating it from a static mesh. ...

Editor cannot handle blueprint structure using an Actor Map variable

UE - Gameplay - Blueprint - Aug 28, 2017

If a blueprint structure contains a map variable with Actor Class Reference as the key, populating the map with a custom blueprint (ActorSet) and adding a variable of the structure to any other blue ...

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 ...

[CrashReport] UE4Editor_Renderer!FBatchingSPDI::DrawMesh() [primitivesceneinfo.cpp:47]

UE - Graphics Features - Jan 3, 2017

Error message: Assertion failed: Mesh.VertexFactory->IsInitialized() [Link Removed] [Line: 45] Source Context: 32 // Keep a reference to the hit proxy from the FPrimitiveSceneInfo, to ensu ...

Crash Occurs When Switching Value on TMap

UE - Gameplay - Blueprint - Mar 15, 2017

The editor seems to be intermittently crashing when switching the value of a Map variable. I've only been able to get this to occur when switching from one type to a Vector at this time. ...

Crash Upon Sequencer Modification of Actor's Array Variable

UE - Anim - Sequencer - Dec 7, 2018

If Sequencer event track modifies an Actor's Integer Variable Array that is exposed to Cinematics, the Editor will crash when the Stop button is pressed. ...

macOS build appears to hang due to UBT deadlocking on ps buffer

UE - Foundation - Cpp Tools - Apr 22, 2021

Licensee reports buffer deadlock issue in System/BuildHostPlatform.cs (lines 283-329). Moving Proc.WaitForExit() to after the for-loop seems to resolve the issue for them.publicoverride ProcessInf ...

Crash in blueprints when opening right-click menu

UE - Gameplay - Blueprint - Apr 22, 2015

Right clicking inside the event graph of a blueprint that is derived from PhysicsCollisionHandler will crash the editor CrashReporter: [Link Removed] ...

OnComponentWake Event does not trigger when the physical body is awoken by a Force

UE - Simulation - Physics - Feb 27, 2025

OnComponentWake Event does not trigger when the physical body is awoken by a Force. The steps described on Steps To Reproduce is enough to replicate this behavior. The OnComponentWake event is only ...