Ensure occurs while duplicating world partitioned level by WorldPartitionRenameDuplicateBuilder commandlet

UE - Engine Scaling - Streaming - World Partition - Aug 21, 2023

The level seems to have been successfully copied. ...

Crash caused by a race condition in Nanite::DispatchBasePass()

UE - Rendering - Features - Nanite - Feb 25, 2026

Nanite::BuildShadingCommands() launches two asynchronous tasks: ShadingCommands.SetupTask ShadingCommands.BuildCommandsTask BuildCommandsTask is responsible for modifying ShadingCommands.Commands ...

Certain UPROPERTY values are not updated during auto-recompile

UE - Gameplay - Blueprint - Aug 4, 2016

Sometimes manual recompile is required to make a blueprint actually recompile data-only changes, but not always. If the last manual compile was with default values, then changes are not updated. If ...

Editor crashes if an interface array variable is reset in the Detail's Pane

UE - Gameplay - Blueprint - Apr 27, 2016

The editor will crash if an array of interfaces is reset using the "reset values" button (yellow arrow) in the Detail's Pane of the editor. Frequency: 4/4 Crashreporter: N/A Regression? (No), is ...

~FStaticMesh() can crash with race condition

UE - Graphics Features - Mar 21, 2017

UDN user reported frequent crashes in FStaticMesh::~FStaticMesh() on DrawListLinks[i]->Remove(false); Crash went away after adding critical sections to FStaticMesh::LinkDrawList(), FStaticMesh::Unl ...

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

UE - Runtime - Simulation - 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 ...

Opening a widget blueprint on Linux causes editor to crash

UE - Platform - Linux - Aug 25, 2016

The editor crashes when attempting to open a widget blueprint. ...

Project breaks if Online Subsystem plugin is disabled

UE - Foundation - Core - Apr 25, 2017

Disabling Online Subsystem prevents the project from loading. On Windows, this produces an error shown in attached screenshot. On Linux, this causes a crash with the attached callstack on project ...

Trace Hit.Z varies strangely based on trace start/end Z

OLD - Anim - May 8, 2017

The Z value of a trace hit will vary based on the Z value of the start/end points of the trace. The larger the start/end Z range, the larger the variance of Hit.Z values. ...

Lighting channels not working as expected when enabling Ray Tracing Shadow

UE - Graphics Features - Lumen - Oct 13, 2020

Non-Ray Tracing Shadows are only cast from lights on meshes assigned to the same Lighting Channel. When enabling Ray Tracing Shadows this is not the case. Lights will still cast Ray Tracing Shadows ...