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 - World Creation - Worldbuilding Tools - 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 ...

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 ...

Assertion Failure: Cascade Particle !bPostTickComponentUpdate in same tick group as Cascade Particle system submission.

UE - Niagara - Apr 18, 2019

Attached Project:  [Link Removed] Since Upgrading project to 4.22, Licensee has been experiencing an Assertion crash in their built game. "I'm not exactly sure why it crashes. It's a very specific ...

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 - Graphics 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 ...

BeginPlay execution order is different when using Game Mode instead of Game Mode Base

UE - Gameplay - Blueprint - Apr 26, 2019

Using Game Mode instead of Game Mode Base causes the Begin Play event to trigger in a different order. This is shown in the reproduction with the Begin Play of the Player Controller and the Game Mod ...

Crash when using ConstructorHelpers on Niagara assets

UE - Niagara - Apr 10, 2019

When using the ConstructorHelpers templated function, FObjectFinder, with Niagara assets, the editor crashes. Tested in 4.21.2 (CL - 4753647), 4.22 (CL  - 5660361),  4.23 (CL - 5806860) ...

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

UE - CoreTech - UObject - 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 - Foundation - 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 ...