Compiling any material in UE 5.5.1 without ShaderCompiler JobCache results in a crash

UE - Rendering Architecture - Shaders - Jan 15, 2025

Compiling any material with r.ShaderCompiler.JobCache=0 causes ShaderCompileWorker to crash. Reproduction steps cause a crash during Editor startup, but this bug may affect other scenarios where mat ...

Popping Ribbon UVs

UE - Niagara - Mar 10, 2025

Please see the Additional Link for related UDN information. The UV popping described can be subtle, depending on settings; it's affected by spawn rate and GPU vs CPU. The popping shown in the gif t ...

Ensure on open if custom Project Setting has a reference to a Blueprint that constructs an object

UE - Gameplay - Blueprint - Jan 16, 2019

An ensure is thrown when opening a project if a custom Project Setting has a reference to a Blueprint that constructs an object. The ensure can be found in the Callstack section below. Regression?: ...

Creating Widget at run time with an exposed variable causes Engine crash with Assertion

Tools - May 8, 2020

If you are using the default values of the In Size the project will run fine, but changing the values will make the engine crash. This was reported and tested in 4.25 (CL-13144385) and reproduced i ...

EQS Context modifications Crashes Editor

UE - Gameplay - Aug 29, 2018

Making changes to the EQS Context and moving the Testing Pawn, the Editor crashes. When reopening the Editor, the context is set and the query does generate from that actor/location. This issue was ...

Editor primitives render incorrectly in stereoscopic with instanced stereo

UE - Platform - XR - Aug 17, 2016

Trigger box icons move around when oculus head movement is used. Found in //UE4/Release-Staging-4.13 @ 3090357 QA-Promotion map Edit: 08-22: This affects volumes as well as their editor icons, upd ...

Using Blend Physics Weight causes skeletal mesh to spin at high speed

OLD - Anim - Mar 5, 2015

When Phyics Blend in the PHAT editor is set between 0 and 1, the user character will spin wildly. User has image of this affecting character in game whereas I was only able to replicate it in the PH ...

Using FEditorModeID for the "Mode" console command does not switch the modes tab

Tools - May 10, 2016

Using the FEditorModeID for the different editor modes does not affect actual modes available in editor Modes tab. Example: Command "Mode EM_Foliage" does not switch to the foliage mode Workaround ...

Child Actor component is duplicated in Standalone Game

UE - Gameplay - Jan 12, 2017

Child Actor component is duplicated in Standalone Game. No other play modes or packaged game are affected. The additional actor will disappear after 1 minute. *This is a regression: Doesn't occur ...

Packaging a Project With Nativize Blueprints Enabled Fails With Setter for an Array of Classes

UE - Gameplay - Blueprint Runtime - Mar 23, 2017

Packaging failure occurs with nativize blueprints enabled when you have an array of classes and you try to set it with an array from an instance of a native C++ class. Found in 4.15.1. Reproduced i ...