User-instanced subobjects owned by a streaming sublevel's Blueprint CDO cannot be garbage collected with the owning world after the sublevel has been reloaded in the editor.

UE - Gameplay - Blueprint - Feb 5, 2020

Strong object reference properties of an 'EditInline'-decorated UCLASS type embedded within a native C++ struct definition can be instanced at edit time by the user as part of a variable's default v ...

ZenGarden or project with MSAA enabled crashes on iPhone 6 and 6+

UE - Platform - Mobile - Jul 19, 2017

Zen Garden crashes on the iPhone 6+ before anything appears onscreen. Occurred on: iPhone 6+ on 10.3.2 Didn't occur on: iPhone 6S on 10.3.2 ...

Race condition in full builds of UE4 engine source

UE - Foundation - Cpp Tools - UnrealBuildTool - Sep 26, 2019

This is a race condition caused by how "Clean.bat", a batch file used during rebuilds, tries to manually rebuild the UnrealBuildTool project when it runs. This causes a spam of UnrealBuildTool build ...

Culling Distances Not Working For Static Mesh in Procedural Content Generation Tool and Foliage Tool

UE - World Creation - Procedural Tools - Mar 28, 2025

When creating Foliage or Procedurally Generated Content the culling settings of the Static Meshes do not apply correctly. As soon as either a minimum or maximum cull distance is set the Static Meshe ...

Spawning a poseable actor with delay crashes

OLD - Anim - Apr 5, 2019

Spawning a poseable actor with a delay causes the Editor to crash. ...

Editor crashes on Mac when launching with the command -MacExplicitRenderer=0

UE - Graphics Features - Jan 19, 2017

Trying to launch the editor with the command -MacExplicitRenderer=0 causes a crash. At the time of the crash, the following line appears in the log:LogMac:Error: appError called: Assertion failed: A ...

[MRQ] Simulating in editor during runtime rendering causes an assertion to fail after rendering is done

UE - Graphics Features - Apr 19, 2022

Simulating in editor during runtime rendering causes an assertion to fail after rendering is done. Repro Rate: 4/4 Tested this in //UE4/Release-4.27 @ CL#18319896 and the issue did not occur there ...

Create Session does not work in a packaged game from any project that has used C++

UE - Networking - Dec 28, 2015

After adding C++ to a content-only project, Create Session no longer works in a packaged game. The following warning appears in the log: LogScript:Warning: CreateSession - Invalid or uninitialized ...

MetalRHI crash locking camera cut to a level sequence in QAGame

UE - Platform - Apple - May 12, 2016

Running into an intermittent crash in MetalRHI when locking to a camera cut in a level sequence. Very similar to [Link Removed] which is an NVIDIA GPU. ...

Framerate drops when using SceneCaptureComponents with a RenderTarget in VR

UE - Platform - XR - May 14, 2018

Using SceneCapture in packaged VR projects causes poor performance. Also observed with SceneCaptureCube Does not occur in 4.18 ...