In editor, sub level instance's streaming state persists incorrectly after toggling Level Behavior without saving

UE - Engine Scaling - Streaming - Level Instances - Jun 11, 2025

When adding a sub level with world partition streaming to a main level where the streaming is also enabled, setting* Level Behavior* of the sub level to Standalone, and saving the result, in the fir ...

iOS Shipping Build using std::thread crashes on launch

UE - Platform - Mobile - Jun 2, 2017

A user is reporting that using the following code in a GameMode class causes shipping iOS packages to crash on launch:void ANOGSSDKGameModeBase::StartPlay() { std::thread([](){ std::clog << "THRE ...

Editor sometimes crashes when trying to compile an Animation Blueprint that extends a class with AnimInstanceProxy

UE - Runtime - Anim BP - Jan 10, 2023

Reproduced 3/3 times, issue does not occur in //UE5/Release-5.0 - CL 20979098 Binary. Confirmed Regression. Seems to work fine when compiled once, but after the 2nd or 3rd time it crashes. ...

Editor Crashes when spawning a Physics enabled object inside another

UE - Simulation - Physics - Sep 22, 2017

Editor Crashes when spawning a Physics enabled object inside another. Regression: Unknown Can Test in Main if requested. ...

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

UE - Rendering - 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 ...

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 ...

Crashes occur when creating a static texture from a non-HDR Cube Render Target in DirectX12

UE - Rendering - RHI - Sep 11, 2023

While working with DirectX 12 in the project settings, the editor crashes by check() code when attempting to create a static texture from a non-HDR Cube Render Target asset. This crash doesn't occur ...

AutoCreateRefTerm does not provide a way to specify that a TArray property within a struct should have a default value created for it if none is provided

UE - Gameplay - Feb 9, 2018

The current implementation of AutoCreateRefTerm does not allow for a default value to be automatically created for a TArray contained within a struct that is passed into a function as a parameter. I ...

Buoyancy is broken in UE5: even BP with Cube SM component (mass is 1kg) and default Buoyancy Component with one default Pontoon falls on bottom of lake

UE - Runtime - Deformable - Jul 26, 2021

Shorter steps:Steps 1-8 from Steps to reproduce (create level with water body)Find BP_BuoyancyExample in Content Browser (Engine>Plugins>Water Content>Blueprints)Place BP_BuoyancyExample above the w ...

Mobile Previewer: Safe Zone Invalid Until Window Resize

UE - Platform - Mobile - Systems - Jul 12, 2021

When the Mobile Previewer loads, the Safe Zone widget is not working properly at startup, and requires a window resize to update to the correct Safe Zone. ...