ES2 Fallback Fails on Nougat Devices that do not support Vulkan

UE - Platform - Mobile - Aug 28, 2016

Discovered this while doing RC candidate testing for 4.13 Works fine in all other use cases: Nougat devices that support Vulkan Marshmallow devices that support Vulkan Marshmallow devices that don' ...

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 ...

VR Preview crashes when the number of players is greater than one

UE - Platform - XR - Aug 18, 2015

If the user has the number of players set to more than one, the VR preview will crash. ...

[CrashReport] USpeedTreeImportFactory::FactoryCreateBinary()

UE - Editor - Content Pipeline - Import and Export - Sep 19, 2017

This is a common and longstanding SpeedTree import crash that has occurred since at least 4.14 for over 100 users. This seems to be the same issue as a previous Jira from 4.10 which was closed wit ...

Physics Constraint Actor: When plasticity is enabled, Drive Position Target is reset to zero on constraint initialization

UE - Runtime - Simulation - Mar 5, 2026

When a Chaos joint constraint is first created, having linear/angular plasticity enabled will unexpectedly force its linear/angular drive position target to zero on initialization, disregarding the ...

Deferred spawned actors can receive BeginPlay before they are finished spawning

UE - Framework - Performance - May 18, 2023

Actors that are deferred spawned on BeginPlay can be added to the world while AWorldSettings::NotifyBeginPlay is still iterating the world's actors and dispatching BeginPlay. AActor::DispatchBeginPl ...

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 ...

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 ...

Crash occur when loading AInstancedPlacementPartitionActor

UE - Editor - May 17, 2022

Crashes when loading an actor that inherits from AInstancedPlacementPartitionActor. There is a serialization size mismatch. ...