[AI] Navmesh does not generate correctly on a plane that has a slope of 45 degrees or more.

UE - AI - Navigation - Sep 23, 2022

Navmesh generation appears to have issues handling terrain and planes that are at 45 degree or steeper angles even if the agent max slope is set to allow for such movement. While the issue occurs at ...

Crash when resizing window using Quad Stereo Buffer

UE - Virtual Production - nDisplay - Oct 2, 2019

We noticed crashes in our application when we attempted to resize a window or switch to full-screen mode. Hence, resizing windows and switching to full screen will result in a crash on Unreal Engine ...

Changing blueprint default values inside arrays only updates loaded child blueprints

UE - CoreTech - Jul 30, 2020

The rules for delta serialization in UE4 are complicated, and the editor tries to hide them from you, which works 90% of the time but can lead to confusion and data loss in other situations. In the ...

[CrashReport] UE4Editor_Engine!LoadSpecialMaterial() [unrealengine.cpp:1523]

UE - Graphics Features - Nov 10, 2017

This is a longstanding crash that has occurred for more than 200 users since at least 4.13. Based on user descriptions this appears to permanently corrupt a project. User DescriptionsI just turned ...

UE 4.6.1 Memory Game Causes Mac OSX to Crash

Tools - Jan 19, 2015

On a Mac running OSX 10.10.1, the launcher crashes when the user selects the "Memory Game" located in the "Learn" section under "Example Game Projects." ...

Niagara Vector Field CPU access Error prevents its use in projects

UE - Niagara - Jan 31, 2020

Niagara VectorFields do not function properly since "Fix CPU Access" changes are not persistently saved. After every Editor restart or reopening projects, the Niagara-VectorField driven Emitter and ...

PhysX Crash In Attached Project During PIE

UE - Simulation - Physics - Jul 29, 2016

The user is experiencing a PhysX crash in their project. They stated that the source files contained in 4.12.5 are different from Nvidia's Github version of 3.3.4, which apparently contains a fix fo ...

When moving actors to the current level, their label is reset and displayed incorrectly on the Scene Outliner until the next time it is refreshed

UE - Editor - Workflow Systems - Jul 14, 2025

This is a regression, it worked correctly up to UE 5.4, but repros on UE 5.5 and 5.6. Also, this seems related to [Link Removed], which was fixed by CL 40649716/40649749 and integrated into UE 5.6, ...

ResavePackages commandlet with -fixupredirects flag won't update asset references on shared collections

UE - Editor - Content Pipeline - Content Browser - Mar 29, 2018

We currently have two methods of fixing up redirectors: the ResavePackages commandlet and the Fix Up option within the editor. While the editor's option correctly handles collections via FAssetFixUp ...

Crash on Device when Deploying Mobile Project with Modulated Shadows and Planar Reflections on iOS 9

UE - Platform - Mobile - Jan 6, 2017

A crash occurs on iOS when deploying the licensee's project using iOS 9 version. The crash does not occur when deployed to a device using iOS 10 version. They believe the crash to be related to Pl ...