DataAsset blueprints have the wrong NativeClass

UE - Gameplay - Nov 18, 2025

UDataAsset's constructor assumes itself to be the native class, and caches that value for use by the asset registry. However, if the data asset type is defined in a blueprint (i.e. subclassing UPrim ...

Cannot create Editor Toolbar Button with the name "Button"

Tools - Apr 19, 2017

The plugin fails to be created with the name "Button". The name button or BUTTON works as a plugin name. If there are some names that plugins cannot be called, then an error/warning message in the o ...

Split Struct pins cause errors when a project is converted to 4.17

UE - Gameplay - Aug 11, 2017

Split Struct pins cause errors when a project is converted to 4.17. You are still unable to split struct pins even if a new variable is created for the struct. Only adding a new variable to the st ...

Map container which has struct type value might be displayed inside unnecessary hierarchy

UE - Editor - UI Systems - Slate - Jan 23, 2020

Essentially, A bug in --[Link Removed]-- comes up with only customized struct property. If a struct doesn't have customization, it can be displayed compact without "Element X" node hierarchy. It i ...

Crash on Mac on exit.

Media Framework - Aug 17, 2020

A licensee reported trouble with a crash on exit on Mac. They discovered that the file AvfMediaPlayer.cpp, on the function Open there is this piece of code:// Force the AV player to not be able to ...

OSS Steam: SteamSocket listen connections do not work after poll group changes

UE - Online - Oct 25, 2021

In 4.27 the logic in SteamSocket.cpp which is part of the SteamSockets plugin was changed to use Poll Groups instead of a removed API function that checked all children of a listen socket. However,  ...

Editor-only blueprints like WidgetBlueprint are not added to cooked asset registry class hierarchy

UE - CoreTech - Aug 10, 2022

Both the Asset Registry and Asset Manager look for all subclasses of UBlueprintCore and use that to search for blueprint classes and construct an inheritance hierarchy. This always works in editor b ...

Switchboard Unable to Launch Multi-User Slate Server in Launcher Builds

UE - Virtual Production - Tools - Switchboard - Jan 14, 2023

Switchboard is unable to launch the Multi-User Slate Server in launcher builds.  This is because the default install location has "Program Files and "Epic Games" in the path (aka folders with spaces ...

Animation attributes - user defined structs containing types defined in plugins cannot be registered

UE - Anim - Runtime - Dec 18, 2023

This issue is caused by us forcing user defined structs to be loaded as part of AttributeTypes::Initialize.  That is called after at the ObjectSystemReady run phase during engine initialization howe ...

Packed Level Actors will create ISMs with inverted normals when a portion of static meshes have negative scales. This is apparent with two-sided materials.

UE - World Creation - Worldbuilding Tools - Feb 17, 2025

Packed level actors will create ISM instances with inverted normals when the selection of meshes used to create the packed level actor contains a subset of meshes with negative scales. This is the ...