MoviePlayer loading screen with FLoadingScreenAttributes::bAllowEngineTick results in high DeltaSeconds tick post-playback

UE - Framework - Feb 16, 2024

IGameMoviePlayer playback of a movie during loading screen lets you set bAllowEngineTick  = true as a parameter. This will make FDefaultGameMoviePlayer manually tick the engine: if (GEngine && bAll ...

Generated world partition maps cause AssetManager warnings

UE - Foundation - Data Pipeline - Cooker - May 29, 2024

When cooking world partition maps, it automatically writes out several maps in a "Generated" folder below the location of the map in the editor. In the repro above, this will create maps such as /Ga ...

[Audio Analysis][Ensure] - Sound Submix Spectral Analyzer Delegate Throws Ensure when Analysis Started Before the Delegate is Added

UE - Audio - Nov 25, 2021

Hit the following Ensure when trying to use the Spectrum Analyser. Also hit this in 4.26 so it doesn't appear to be a regression. Occurs with any of the following Band Settings or when creating you ...

Unable to launch project from Visual Studio using installed engine build

UE - Foundation - Build - Farm - Feb 23, 2017

When a code project's engine association is switched to a local binary version of a source engine, the project will fail to open from within Visual Studio. Error message says that UE4Editor-Project ...

Python crash the engine at exit.

UE - Editor - Workflow Systems - Oct 25, 2022

A UDN reported various crashes at exit in the embedded Python library. I was able to repro the issue in Release-5.1 and trace it back at the point where python runs its garbage collection in Py_Fina ...

Crash in AWorldDataLayers::InitializeDataLayerRuntimeStates() when quickly unloading then loading a sub-world partition

UE - World Creation - Worldbuilding Tools - Data Layers - Mar 6, 2025

From licensee: Since we integrated 5.5, we are experiencing a crash in AWorldDataLayers::InitializeDataLayerRuntimeStates() on this line check(ActiveDataLayerNames.IsEmpty() && LoadedDataLayerN ...

check(bRenderStateCreated) fires in SendRenderDynamicData_Concurrent called from FRegisterComponentContext::Process

UE - Rendering - Architecture - RHI - May 18, 2026

FRegisterComponentContext::Process() in ActorComponent.cpp iterates over SendRenderDynamicDataPrimitives and calls SendRenderDynamicData_Concurrent() on each. The existing guard checks ::IsValid(Pri ...

When welding collision between Third Person UE4 Mannequin's left foot ball, to left foot in physics tab results in an Engine crash.

UE - Simulation - Physics - Jan 30, 2019

When using a Third Person UE4 Mannequin, Opening the Physics asset tab, and welding the collision between left foot ball, to left foot results in an Engine crash. Additional Note: Using the same ...

Directly opening a modified map asset of a streaming sublevel does not always force it to be reloaded (inconsistent with other map open behaviors)

UE - World Creation - Worldbuilding Tools - Feb 10, 2026

When the level currently being edited has unsaved changes and the user opens a new one, the Editor asks if the changes should be saved. If the user answers negatively, the level asset is reverted to ...

Blueprint CDO contains removed component from parent class

UE - Gameplay - Blueprint - Apr 28, 2015

Blueprint CDO contains removed component from parent class. From the AnswerHub post: "It appears that if a component is removed from the C++ class, the CDOs for all of the blueprints remain unchang ...