In -game in Editor, if streaming-in a LevelInstance and initialize its world partition, then leaving that cell and make it go outside the streaming grid, to re-enter it again, will trigger a check(!StreamingPolicy) if no GC has happened during that time.

UE - Engine Scaling - Streaming - World Partition - Jan 27, 2025

This crash can be fixed by adding a couple of || IsRunningGame() like it is done here:    FGenerateStreamingContext Context = FGenerateStreamingContext()        .SetLevelPackagesToGenerate((bIsPIE ...

Editor crashes when overriding Texture Collection in Material Instance

UE - Rendering - Architecture - Aug 6, 2026

When a Material uses the DefaultTextureCollection and a Material Instance overrides it - or vice versa - the Editor will crash. Note: bindlessconfiguration=Minimal or higher must be enabled to use ...

MediaFramework movies not playing properly in Shipping

Media Framework - Nov 7, 2017

`check(Samples.Pop());` this kind of `Pop()` inside of a `check()` is in a few places in MediaSampleQueue.h and MediaSamples.cpp but `check()` expands to nothing in Shipping/Test, so, required work ...

Suspension CoM calculations don't update with mass.

UE - Simulation - Physics - Dec 15, 2016

UWheeledVehicleComponent calculates the Suspension settings only when the physics state is first created. When CoM is set through the editor, the vehicle is constructed with the appropriate offset ...

Using multiple SceneCapture2D with DLSS Enabled crashes UE

UE - Rendering - Features - Nov 22, 2024

A licensee is reporting a crash (or rather a check fail) in Sceneview.cpp which happens with when a SceneCapture2D is used with DLSS enabled. He has a fix, and wants to share it with us for integrat ...

SceneCaptureComponent2D leaks a ton of memory in a Packaged Build

UE - Virtual Production - Mar 12, 2020

This was initially reported in VR but the leak happens in a non-VR setup and environment. GPU utilization jumps to 84% in 4.23.1 and 98%+ in 4.24.3, 4.25, and 4.26. Tested GPUs were GTX 980 and GTX ...

UObjects returned from "Get Item Children" in a TreeView widget causes an engine crash, due to invalid pointers

UE - Core - Systems - Jun 9, 2020

UObjects returned from "Get Item Children" in a TreeView widget causes an engine crash, due to invalid pointers. User has proposed the following fix: The best fix is probably such: When Slate list ...

Crash when using StaticDuplicateObject with mismathced Source and Destination class types

UE - Core - Systems - Jun 19, 2025

Starting in Unreal Engine 5.4, StaticDuplicateObject internally switched to using Unversioned Property Serialization (UPS) for performance reasons. However, UPS assumes the source and destination ob ...

Static mesh's material slot's cast shadow does not require a build of StaticLight

UE - Graphics Features - Dec 7, 2017

If static mesh's material slot's cast shadow is changed, UE4 does not show "LIGHTING NEEDS TO BE REBUILT". I solved it with the following fixes. StaticMeshEditorTools.cpp void FMeshSectionSettin ...

Building Lighting will Generate Additional Lightmaps after Rotating Lightsource

UE - Graphics Features - Jul 7, 2015

Lightmap sizes seem inconsistent after rotating a light source and rebuilding the lighting. This causes concern about file sizes when packaging the project that is using baked static lighting. The ...