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 ...

Mobile Previewer: Safe Zone Invalid Until Window Resize

UE - Platform - Mobile - 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. ...

Using dynamic bindings in a code class will result in the bindings becoming a permanent part of any Blueprint created from that class if a hot reload is performed.

UE - Foundation - Core - Mar 26, 2015

If dynamic bindings are being used in a custom code class from which Blueprints are derived, any hot reload will make the bindings a permanent part of the Blueprint and they cannot be removed or cha ...

Editor Crashes when Isolating a Material Element on Skeletal Meshes with Ray Tracing Enabled

UE - Graphics Features - Lumen - Jul 3, 2019

With ray tracing turned on, clicking on the isolate material option next to a material slot on a skeletal mesh with more than one material slot, causes the editor to crash. Found in 4.22 CL# 7053647 ...

Internal Compile error received from rearranging Format Text nodes

UE - Gameplay - Blueprint - Dec 18, 2014

Internal Compile error received from rearranging Format Text nodes Output Log of Error: LogBlueprint:Error: [compiler] Error Internal compiler error inside CreateExecutionSchedule (site 2); please ...

Fullscreen Editor Crash when setting both IndexBuffers to False

UE - Graphics Features - Jul 22, 2019

When setting both IndexBuffers to False the Editor will crash when attempting to use Fullscreen mode with F11. ...

A welded hierarchy blocks updates to collision settings on all but the root primitive. Calling SetCollisionResponseToChannel on the children won't work.

UE - Simulation - Physics - Nov 22, 2024

A welded hierarchy blocks updates to collision settings on all but the root primitive. Calling SetCollisionResponseToChannel on the children won't work. The licensee noticed that IPhysicsProxyBase* ...

Crash in VehicleGame Standalone game when attempting to drive

UE - Graphics Features - Oct 6, 2016

This was on an Nvidia Macbook Pro. Doesnt crash on an AMD iMac. ...

Switching raytracing console variable in runtime can crash engine.

UE - Graphics Features - Lumen - May 13, 2020

Licensee reported that is caused by missing ECVF_RenderThreadSafe flag in these console variable definitions. r.RayTracing.Shadows r.RayTracing.AmbientOcclusion r.RayTracing.Reflections Here is a ...

Instanced static meshes fire an erroneous performance assert about loose parameters.

UE - Graphics Features - Sep 4, 2019

 "This ensure is intended to catch regressions where rendering programmers add a loose parameter to LocalVertexFactory, breaking dynamic instancing on regular static meshes.  InstancedStaticMeshes c ...