In-editor hitch when deleting one actor in a world with many loaded actors

UE - Core - Systems - Nov 17, 2023

When editing a level with many actors (1000+), deleting an actor results in a noticeable hitch: the editor becomes unresponsive for seconds. This hitch becomes longer the more actors are loaded and ...

Crash When Assigning a Static Mesh to the "Sample Static Mesh" Module

UE - Niagara - Jun 28, 2018

When assigning a static mesh to the "Sample Static Mesh" module, the engine will crash as soon as you select a mesh and click "Fix Now". If the mesh already has CPU access enabled it will crash as s ...

Edits of node properties that are not stored on pins do not diff correctly

UE - Gameplay - Blueprint Editor - Oct 2, 2015

Currently details changes to the following are not noticed by the Diff tool when diffing AnimBPs:State Machines (i.e. Max transitions per frame)Transition rulesConduitsStates This also affects non- ...

Nvidia Graphics Drivers cause editor menus to flicker and disappear after using the editor for an extended period of time

UE - Graphics Features - Apr 16, 2021

This issue seems to be occurring on a variety of Nvidia cards. So far, I haven't seen any indication that it is affecting AMD graphics cards. The majority of the reports have indicating that the pro ...

FBX Import flips faces of mesh on Import for static meshes

UE - Graphics Features - Jan 29, 2016

User is reporting that this is happening with some, but not all meshes. I didn't see anything out of the ordinary when looking at the asset in 3Ds Max, and the asset will import correctly into 4.10. ...

"Combine Meshes" Breaks Material Slot Assignment

Tools - Jan 18, 2017

When importing an FBX with several different meshes and multiple materials with "Combine Meshes" enabled the materials will get assigned to incorrect portions of the mesh. I've included a version o ...

Crash after network disconnection/pulling network cable

UE - Networking - Jul 11, 2019

A very unfortunate bug shipped in 4.22 that causes a crash in many cases when a client is disconnected from the network, such as when unplugging the network cable. This will be a cert failure on con ...

Landscape Layer Blend generates bad code for preview shader

UE - LD & Modeling - Terrain - Landscape - Sep 23, 2019

It breaks only when compiling the preview shader. Adding a preview weight to the Layer0 on the Layer Blend node fixes the problem. The source of the bug is in UMaterialExpressionLandscapeLayerBlend ...

Crash when entering Path Tracing view mode if r.Decal.NormalReprojectionEnabled true

UE - Graphics Features - Path Tracer - May 16, 2025

Cash when entering Path Tracing view mode if r.Decal.NormalReprojectionEnabled true The licensee has reported: This crash happens because the DeferredShadingRenderer tries to extract the normal GBu ...

DataTable::LoadStructData allocating wrong size

UE - Foundation - Core - Oct 5, 2016

Pointed out by a licensee here: UDataTableを読みこんだ際のメモリ破壊について When reading the `UDataTable, in DataTable::LoadStructData()` the contents of the struct are interpreted[Image Removed], but the size of ...