Uniform scaling in the viewport not working as expected when additive mode is enabled

UE - Editor - Workflow Systems - Apr 2, 2022

The uniform scaling does not work as expected Repro Steps: 1) Add a cube to a level 2) Set the scale (X = 16, Y=9, Z=9) 3) Click the Lock icon to activate the Uniform Scale feature 4) In the viewpor ...

Importing static mesh while a PIE session is running permanently breaks nanite on the asset

UE - Editor - Content Pipeline - Import and Export - Mar 12, 2025

Importing a Static Mesh during PIE can cause it to never enable Nanite, even if it reports that Nanite is enabled. To re-enable Nanite on the mesh, the asset needs to be deleted and imported again ...

Volumetric Translucent Shadows will only work if you select the mesh, doesn't show up in game

UE - Graphics Features - Aug 18, 2015

When using Volumetric Translucent Shadows for static meshes the shadows will only work if the mesh is selected. When the mesh is deselected it will not render. This worked in 4.8.3, but is broken ...

Building for Gear VR Distribution fails due to missing Oculus lib

UE - Platform - XR - Jun 7, 2017

Users have reported that building for Distribution on Gear VR results in failure due to a missing Oculus library. The error they receive is as follows: UATHelper: Packaging (Android (ETC2)): [javac ...

Behavior Trees cannot be saved if the Blackboard assigned to it was opened before opening the Behavior Tree from the Content Browser

UE - AI - Nov 2, 2015

Behavior Trees cannot be saved if the Blackboard assigned to it was opened before opening the Behavior Tree from the Content Browser. Reproduced in 4.8.3 binary, 4.9.2 binary, 4.10 Preview 3 binary ...

Displaying Revision control history for a file ending in an "undo" of a revision can cause a crash

UE - Editor - Workflow Systems - Jun 18, 2024

This crash is caused by how source control history is managed and shown. In this specific case the source control software is Perforce. As written in the repro steps, it can happen to any uasset tha ...

Ensure triggered in FBoundsCacheElement::GetValue when adding ISM instances in Construction Script

UE - AI - Oct 8, 2025

An ensure is triggered in FBoundsCacheElement::GetValue when adding instances to an InstancedStaticMeshComponent inside a Blueprint’s Construction Script. This occurs when the ISM component is navig ...

[CrashReport] UE4Editor_BlueprintGraph!BlueprintActionFilterImpl::IsEventUnimplementable() [blueprintactionfilter.cpp:588]

UE - Gameplay - Blueprint - Jun 1, 2016

This crash has been reported through the 4.12 Previews and is continuing to occur in the 4.12.0 release. Additional information about this crash is not available at this time, however it may be the ...

ModularGameplay and other runtime plugins have wrong LoadingPhase

UE - Gameplay - Jun 30, 2022

Plugins that provide blueprint-accessible libraries generally need to be set the PreDefault LoadingPhase so they can be properly loaded before game-specific data that loads early in the Default load ...

UV Flipping Mode Causes Stretching of Particles

UE - Niagara - Nov 17, 2017

If "UVFlipping Mode" under Rendering on the Required node of an emitter is set to anything other than "None," the particles can become stretched and distorted. As a workaround, I have discovered th ...