Template function TSparseArray::PointerToIndex does not compile

UE - Foundation - Core - May 26, 2020

Error:  C:\Program Files\Epic Games\UE_4.25\Engine\Source\Runtime\Core\Public\Containers/SparseArray.h(778): error C2440: '-': cannot convert from 'const TSparseArrayElementOrFreeListLink<TAlignedBy ...

Blueprint Actor cannot delete implemented interface when Interface is converted to an Event.

UE - Gameplay - Blueprint - Dec 11, 2019

In Editor, When you remove a return value parameter from a Blueprint Interface function's Output Category. (so there are no return values), it becomes an event. In any Blueprint that implements the ...

BC7 Format in Texture Asset Mip Maps are not correct

UE - Graphics Features - Apr 18, 2016

When enabling BC7 compression format for a texture in a project that has SM4 disabled will result in the last two Mip Levels being gray. This happens on any texture size. The number o mip levels may ...

Red 'X' Persists after Duplicating Overlapping Stationary Lights and Setting them to Static or Movable

Tools - Sep 15, 2016

Duplicating a group of overlapping stationary lights that produces the red 'X', and setting the copied group to 'Static' or 'Movable' will maintain the red 'X' on one of the light components. Note ...

Crash after adding an AI Perception component to a parent and child character

UE - Gameplay - Sep 14, 2017

Crash after adding an AI Perception component to a parent and child character. First they both must have had AI Perception components > Compiled and saved > Then both AI Perception components delete ...

A duplicated component in the blueprint editor is invisible and the pivot stays at 0,0,0 until compiled

UE - Gameplay - Blueprint - Jun 19, 2015

A duplicated component in the blueprint editor is invisible and the pivot stays at 0,0,0 until compiled User Description: Since 4.8 if I duplicate a child actor component in the viewport the dupli ...

If the DataLayerAsset name or asset path changes, Actors registered to it will ignore the DataLayer's settings

UE - World Creation - Worldbuilding Tools - Feb 5, 2023

If you change the DataLayerAsset name or asset path, all Actors registered with that DataLayer will ignore that DataLayer's settings. Specifically, even if you set the DataLayer to the Unloaded stat ...

Copying a destructible mesh in the viewport loses reference to assigned mesh in the details panel

UE - Simulation - Physics - Destruction - Nov 4, 2014

BRANCH: MAIN CHANGELIST: 2346079 PLATFORM: Windows DESCRIPTION: When copying a Destructible mesh in the viewport the Destructible Mesh component will not be shown for the copied mesh. The mesh can ...

Cook Non-Determinism in USplineComponent

UE - Editor - Feb 25, 2026

1. Non-Deterministic LastAuthority Serialization LastAuthority is assigned in USplineComponent::Serialize. Its value depends on the order in which the object and its archetype are serialized, leadi ...

Blueprint PaperTileMap Component not Rendering while in Mobile Preview or Launched on Device

UE - Gameplay - Paper2D - Jun 12, 2015

A blueprint with a PaperTileMap component will not render when played through the 'Mobile Preview' or as a packaged project. If the Tilemap alone is dragged into the viewport it renders fine when p ...