[CrashReport] UE4Editor_LevelEditor!FMulticastDelegateBase<FWeakObjectPtr>::RemoveAll() [multicastdelegatebase.h:81]

Tools - Oct 26, 2017

This is a trending crash in 4.18.0. One case of this callstack occurred in 4.17.1, but then numerous have occurred in 4.18. Users have not provided any descriptions of their actions when the crash ...

Tabbing out of exclusive fullscreen leaves the window & backbuffer in an incorrect state

UE - Editor - UI Systems - Apr 24, 2020

With windows 10 there has come some new swap chains, which unfortunately messes some things with regards to fullscreen up. We've fixed a bunch in the renderer (which would downright cause crashes), ...

Possible data loss/corruption when loading levels in editor

UE - Gameplay - Jul 18, 2018

Reported behavior: Given Level_A which contains object_X, where object_X references Level_BDeleting object_X causes AssetRenameManger to check if we need to patch up other levelsLevel_B is load ...

Failure to sign when packaging for iOS Distribution when using Remote Compile from a code project on Windows

UE - Platform - Mobile - Feb 20, 2019

Packaging for iOS Distribution from Windows using Remote Compile results in a failure during the signing portion. This seems to be caused by a hardcoded "false" for a property that is used to determ ...

SketchUp UV scale is not consistent for Datasmith imports.

TM - Interoperability - Dec 6, 2024

This is not a regression.  We have 2 issues here.  First we have different tiling for the different materials, since the way sketchup handles texture scale. They scale the UVs of the object instead ...

PCG sampling of RVT does only works when sampling the first texture layer

UE - World Creation - Procedural Tools - PCG Component - Dec 11, 2025

The logic for selecting a page table texture in FVirtualTexturePageTable::Initialize() uses the indexing for texture layers (index 0-7) to fetch from the page table textures (index 0-1). All RVT for ...

References to Data Assets that inherit from Blueprints may be broken during reinstancing

UE - Gameplay - Blueprint - Nov 30, 2020

It is possible to create new Data Asset instances in the editor that inherit from a blueprint-defined subclass of UDataAsset. This flow is not very well supported, and generally it is safer to just ...

Socket Snapping in level editor no longer works

Tools - May 14, 2018

The Socket Snapping level editor action no longer works in 4.19/4.20, it worked in 4.18 but regressed. It still attaches but it's set to maintain it's world position, so it doesn't actually snap. T ...

UBT Output log encoding does not match if non-ASCII characters are in the UBT output

UE - Foundation - Cpp Tools - UnrealBuildTool - Nov 21, 2019

UBT Output log encoding does not match if non-ASCII characters are in the UBT output. Before UE4.23, UBT output encoding problems only exist in the editor "Compiler Log" under Developer Tools, and i ...

Particle Mesh Emitters Cause Heavy FPS Stutter

UE - Graphics Features - May 4, 2018

Per User: After updating my project from 4.18 to 4.19, I started getting huge FPS drops at regular intervals. I managed to trace back the issue to particle systems with mesh emitters and could repr ...