Unreal Engine Issues
Unreal Engine Issues
Crash when using ComplexCollisionMesh and the ComplexCollisionMesh has more material index than drawing mesh's material index
UE - Simulation - Physics - Mar 2, 2020When using ComplexCollisionMesh of StaticMesh asset, at the time of hit, the physical material refers to the material of the drawing mesh side using the material index of the collision mesh side. T ...
Event Tick is not running once packaged
UE - Gameplay - Components - Jul 20, 2015Event Tick works when it's running on Windows however once it's packaged or even launched onto all platforms, the event tick does not work as anticipated. This happens on all platforms. *Project ca ...
[CrashReport] UE4Editor_CoreUObject!FMemoryWriter::Serialize() [memorywriter.h:42]
UE - Foundation - Core - Jul 24, 2017This is a common cook crash affecting users in 4.16. It is possibly the same issue as described in [Link Removed] for past engine versions. Source Context 33 virtual void Serialize(void* ...
Unfocused Standalone window has reduced performance
UE - Rendering - Architecture - RHI - Aug 25, 2020User description: When I run two windowed standalone instances to test multiplayer, the unfocused window gets about 2-5 fps...but if I focus on it, smooth 120fps, yet the opposite screen is now onl ...
Inconsistent ListView entry sizes can prevent the ListView from being scrolled to the bottom
UE - AI Workflows - UI Systems - Slate - May 4, 2022Since the contents of a ListView are virtualized, the ListView estimates the size of the scroll box's contents based on the on-screen elements. This can lead to some situations where DistanceFromBot ...
Unreal Engine Fails to Launch with Vulkan SM6 RHI and RenderDoc Auto-Attach Enabled
UE - Rendering - RHI - Dec 3, 2025When launching Unreal Engine with the Vulkan RHI, SM6 and RenderDoc Auto Attach on Startup enabled, the engine fails to initialize with the error: “A compatible Vulkan Driver is required to run the ...
MotionWarping does not recognize new MontageInstance with the same montage
UE - MVF Character - Animation - Jan 11, 2023When the same AnimMonotage is played again while moving with MotionWarping & RootMotion, UAnimNotifyState_MotionWarping does not recognize it. From licensee: The issue was that in URootMotionMod ...
Regarding TObjectPtr performance regression
UE - Core - Systems - Jul 13, 2026This is from the linked EPS case: ============================== When 5.0 first introduced TObjectPtr, the guidance was that it would compile down to raw pointer access in Shipping builds to ensu ...
[CrashReport] Assertion failed: !bRequireNormalization - UE4Editor_Landscape!ULandscapeComponent::ReplaceLayer()
UE - LD & Modeling - Terrain - Landscape - Jul 19, 2017This is a common crash affecting users in 4.16, and has occurred since at least 4.14. Over 200 unique users have been affected, though they have provided little information. User DescriptionsI am a ...
[CrashReport] Mac crash - UE4Editor-Slate.dylib!SMenuAnchor::SetIsOpen()
UE - Platform - Apple - Sep 14, 2017This 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 ...