Swarm: Not able to set number of processors to use for Swarm from the UI

UE - Graphics Features - Aug 25, 2015

There is a setting called "LocalJobsDefaultProcessorCount" in the Developer Settings tab in Swarm. After the change to make Lightmass build asynchronously while the user keeps working, this set ...

Frequent ensure opening meshes on Mac, locks up AMD machines

UE - Graphics Features - Jun 6, 2017

REGRESSION No, I was able to reproduce the hard lock in 4.16.1. A frequent ensure occurs when opening static or skeletal meshes on Mac. Doesn't reproduce 100% of the time, but I've gotten it about ...

Navmesh seems to have buggy behavior when interacting with HISMCs that programmatically set mesh via SetStaticMesh.

UE - AI - Mar 6, 2020

Both versions works correctly if HISMC is pre-placed (generated in ConstructionScript). Only when generated dynamically does it fails. The Navmesh isn't being updated after SetStaticMesh and AddInst ...

C# UHT fails to recognize delegates declared in another class's namespace

UE - Foundation - Cpp Tools - UnrealHeaderTool - Dec 14, 2022

Repro Rate: 3/3 This issue occurs in the live build //UE5/Release-5.1 at CL 23058290. This issue has also been regression tested against //UE5/Release-5.0 at CL 20979098 and is confirmed to be a r ...

If any light source is deleted, and a single light has its visibility state changed in LightMixer, all the other lights in the scene that were invisible turn visible

UE - Virtual Production - Tools - Jul 31, 2025

If any light source is deleted, and a single light has its visibility state changed in LightMixer, all the other lights in the scene that were invisible turn visible. The behavior only shows after d ...

Importing multiple SpeedTree assets that use the same texture will not assign correctly

UE - Graphics Features - Sep 25, 2015

When importing multiple SpeedTree assets that use the same material will cause one to import blank (black) materials and assigned. This happens when importing into the same folder, however, if impor ...

AI characters with Navigation Invokers that are spawned during Play do not generate a nav mesh around them if Runtime Generation is set to Dynamic Modifiers Only

UE - AI - Sep 17, 2015

With Generate Navigation Only Around Navigation Invokers enabled and Runtime Generation set to Dynamic Modifiers Only, AI characters with Navigation Invokers do not generate a nav mesh around them i ...

Apex Cloth disappears when Setting Custom Time Dilation to Zero

UE - Simulation - Physics - Character - Aug 24, 2016

Apex Cloth assets disappear if you set the Custom Time Dilation to 0.0. You can workaround the issue by setting the Custom Time Dilation to 1.0, and then use the 'Force Cloth Next Update Teleport a ...

Make Lidar Point Cloud Point Node has had the Location input change from a Vector to a Vector 3f

UE - Gameplay - Oct 12, 2022

Tested in: //UE4/Release-4.27 CL 18319896 Input pin was of type Vector //UE5/Release-5.0 CL 20979098 Input pin was of type Vector 3f //UE5/Release-5.1 CL 22346211 Input pin was of type Vector 3f Th ...

Unable to delete levels with Particles in them

UE - Gameplay - Oct 9, 2019

The engine is unable to Level that has a Blueprint actor with a child actor component that has a particle system component. The follow message pops up: World /Game/LevelName.LevelName is in use. — ...