Crash in FUniformExpressionSet::FillUniformBuffer trying access deleted UTextureCollection

UE - Rendering - Architecture - May 30, 2025

Crash in FUniformExpressionSet::FillUniformBuffer trying access deleted UTextureCollection (Experimental in 5.6). The licensee describes their crash, their analysis, and a proposed fix: This crash ...

Adding Niagara system to a projectile causes a crash

UE - Niagara - Jul 29, 2019

Adding a Niagara system to a BP_Projectile in a C++ First Person Project  and then restarting it causes the editor to crash. Tested in 4.21.2 (CL - 4753647), 4.22.3 (CL - 7053647), 4.23 (CL - 744 ...

Initializing custom Component on Actor in constructor causes odd hierarchy and details panel issues

UE - Gameplay - Blueprint - Feb 19, 2019

When testing with a simple setup, as follows: MySceneComponent has a UProperty(VisibleAnywhere, BlueprintReadOnly) of a USphereComponent pointer, initiated in the Constructor AMyActor has a UProper ...

Focus mode in the Editor does not handle Actors without PrimitiveComponent correctly, treating them as if they were at the origin (0,0,0), skewing the camera placement.

UE - World Creation - Worldbuilding Tools - Nov 18, 2024

Focus mode in the Editor does not handle Actors without PrimitiveComponent correctly, treating them as if they were at the origin (0,0,0), skewing the camera placement. Some Actors like the WorldDat ...

Updating Material does not update platform stats in derived Instance

UE - Rendering - Architecture - Materials - Nov 26, 2024

It would seem that updating a material does not update the associated platform stats in a material instance editor, only the parameters. Can workaround by manually invoking shader compile in the ma ...

Crash: Unhandled exception UE4Editor_Renderer!FMobileBasePassMeshProcessor::Process

UE - Graphics Features - Mar 14, 2019

HUD can cause a crash when used with Mobile. "When running from visual studio exception happens here: https://github.com/EpicGames/UnrealEngine/blob/4.22/Engine/Source/Runtime/Renderer/Private/Mobi ...

UMG widget callbacks do not set PIE context in editor

UE - Editor - UI Systems - May 21, 2018

This is from a UDN post. Several gameplay functions, such as level streaming and SoftObjectPtr resolution, depend on the GPlayInEditorID being set when that code is executed in PIE in the editor. T ...

The light in the Blueprint Editor's Preview Scene does not respond to any lighting channel but 0.

UE - Framework - Blueprint Editor - Jun 28, 2024

In the Blueprint Editor, Primitive Components can be configured to respond to Lighting Channels 0, 1, and/or 2. However, if channel 0 is disabled (even with another one enabled), the Preview Actor's ...

Regression: Android Media Player Material - Plays on flipped normal

UE - Platform - Mobile - Jul 25, 2019

Media Player Texture/Material is playing on opposite mesh normal. Confirmed on Note 4, Pixel XL and Oculus Quest Did NOT reproduce with Vulkan. Video Material is white on 4.22 and 4.23 iOS ...

Landscape Splines in Partially Loaded World Partition Levels Can Cause Nanite Landscape Invalidation

UE - Graphics Tools - Terrain - Nov 7, 2025

Certain placements of landscape splines in world partition levels can cause Nanite landscape proxies to invalidate, and switch back to their non-nanite version. This happens when specific regions of ...