Niagara module "Beam Emitter Setup" makes attribute Emitter.BeamID flick between -1 and LoopCount every frame

UE - Niagara - Content - Mar 6, 2026

When working with beam and ribbon effects in Niagara, Emitter.BeamID is used to fill Particles.RibbonID so that a looping emitter can spawn multiple discrete beams. Emitter.BeamID is assigned by mod ...

Editor crashes when changing skeletal mesh if another skeletal mesh component is attached when using master pose node

OLD - Anim - Jan 27, 2020

The crash only occurs if the additional skeletal mesh component is used with Set Master Pose Component (see ToggleAttach function in the TopDownCharacter BP). It doesn't seem to matter what mesh we' ...

Set user focus for player 0 will cause other local players to lose input

UE - Gameplay - Input - Feb 28, 2019

When the player at index 0 sets its user focus it will cause other players to lose input. This does not occur when setting the user focus of players with an index higher than 0. ...

GeometryCollectionPhysicsProxy::FieldParameterUpdateCallback() not removing invalid Commands, leading to performance issues

UE - Simulation - Visual - Aug 30, 2025

GeometryCollectionPhysicsProxy::FieldParameterUpdateCallback() not removing invalid Commands, leading to performance issues. The licensee has provided their analysis: We seem to have stumbled acro ...

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 ...

Exception generated launching Horde Agent built with 5.6

UE - Foundation - Horde - Server - Jul 28, 2025

The source of the problem seems to be using IOptionsSnapshot with a Singleton. Per the MS documentation for IOptionsSnapshot, "Is registered as Scoped and therefore can't be injected into a Singleto ...

PATH not passed to NMake script when building Android from Visual Studio

UE - Foundation - Cpp Tools - UnrealBuildTool - Jan 25, 2023

After upgrading from UE5.0.3 to UE5.1, we started seeing this error when trying to build Android Development from Visual Studio (VS2022 17.2.1): Running UnrealBuildTool: dotnet "..\..\Engine\Binari ...

Unable to interact or collide with geometry collection after Removal on Sleep or Break timer finishes, yet unbroken piece continue to render

UE - Simulation - Core - Dec 18, 2025

Context: A static mesh is able to have a geometry collection generated from it using the Fracture editing mode. It can be fractured in many different ways, and when acted upon by a chaos field agent ...

Crash when upgrading Nvidia GFX driver from Version 457.85 with open Project

UE - Graphics Features - Nov 18, 2022

Repro Rate: 5/5 Summary: When opening a Project in UE version 5.1.0 with Nvidia GFX driver version ###, the user is notified that there are known issues with this driver through a pop-up:WARNING: K ...

Illegal reference to private object when cooking a child level sequence with a time warp track

UE - Anim - Sequencer - Apr 28, 2025

Slack: [Link Removed] Another Slack: [Link Removed] Cook error:UATHelper: Cooking (Windows): LogSavePackage: Warning: UATHelper: Cooking (Windows): Referencers of MovieSceneTimeWarpSection /Gam ...