Failed Import for Spline Component Error Appears on Restarting Level

UE - Gameplay - Blueprint - Jul 5, 2016

When creating and declaring a Spline Component in code, placing an instance of a blueprint derived from that class in the level causes a failed import message to appear upon restarting the level. ...

World Partition - Deleted actors can become unloaded prior to saving

UE - World Creation - Worldbuilding Tools - World Partition - Apr 11, 2025

In world partition levels, deleted actors can become unexpectedly unloaded prior to saving, causing loss of work. Specifically, this issue occurs after the undo history has been cleared (either manu ...

WorldPartitionConvertCommandlet hits an assert when converting a persistent level that contains a sub-level with a landscape

UE - World Creation - Worldbuilding Tools - Nov 7, 2025

Context: The Window tab allows a user to open the Levels window in order to add a sub-level to a persistent level. For Unreal Engine 5.0 and beyond, World Partition has made the Levels window obsole ...

Packaged Project with Media Player Asset 'From Memory' Crashes and Corrupts Project

Tools - Feb 9, 2015

There is no Callstack associated with this crash. And I was unable to reproduce this in main due to a known issue when switching the 'Stream Mode' to 'From Memory'. When packaging a project in 4.6. ...

AddChildActorComponent in Construction Script Causes Pending Kill Error

UE - Gameplay - Blueprint - Feb 16, 2016

When using AddChildActorComponent in the construction script of an actor and attempting to get a reference to the child actor that is stored in a variable on Event Begin Play, the editor throws erro ...

Details panel for Actor Component is blank in any Blueprint that derives from a code class using that Actor Component after the Actor Component's class name is changed

UE - Gameplay - Blueprint - Dec 20, 2018

Changing the name of an Actor Component code class in a project results in any existing Blueprints that derive from code classes that use that Actor Component to not display the Actor Component's pr ...

Creating a function with parameter type TEnumAsByte<MyEnum> will crash while compiling

UE - Editor - Jan 11, 2022

This is a regression.This does not affect UE5. Creating a function with parameter type TEnumAsByte<MyEnum> will crash while compiling. In 4.26 and UE5 the code compiles without issue, and the user ...

FSlateApplication::OnControllerAnalog triggers a MouseLeftClick event to be added to the input stack.

UE - Gameplay - Input - Jun 3, 2016

It appears that FSlateApplication::OnControllerAnalog triggers a left mouse click to occur on mobile platforms. If developers haven't properly avoided hooking up delegates to the InputComponent for ...

Blueprint Cannot Give Niagara CPU Access To Skeletal Meshes Added From Blueprint

UE - Niagara - Apr 4, 2019

When a user tries to add a skeletal mesh component to a blueprint with a niagara system to use the skeletal mesh with that niagara system, the niagara system will stop rendering because it does not ...

Issue during the CapturingScene phase when having Nanite mesh as source component for HLOD Generation

UE - World Creation - Worldbuilding Tools - Feb 17, 2026

When generating the textures for Approximate HLOD layers, the Nantie geometry is very low resolution, resulting in the captured textures fitting the actual HLOD geometry poorly. This creates visual ...