AttachRootComponentToActor being used over a network can cause an Ensure (previously an Assertion) to be triggered.

UE - Gameplay - Jan 11, 2016

This is a continuation of [Link Removed]. The previous ticket changed an Assertion to an Ensure in order to stop a crash from occurring, and stated that a more complete fix would be coming in 4.10. ...

LogUMG: Error: The requested size for SRetainerWidget is 0. W:739 H:0 when opening or updating a curve using the StackedCurve view

UE - Anim - Sequencer - Feb 6, 2023

The following error is generated in the Output log whenever a Wave Table is opened or any of the graphs are modified. It also occurs when adding an Input to a Sound Modulation Parameter patch or add ...

Switchboard Unable to Launch Multi-User Slate Server in Launcher Builds

UE - Virtual Production - Tools - Switchboard - Jan 14, 2023

Switchboard is unable to launch the Multi-User Slate Server in launcher builds.  This is because the default install location has "Program Files and "Epic Games" in the path (aka folders with spaces ...

Asset values change when the Editor is out of focus when using Maya or Web Browser

Tools - Jul 18, 2018

When switching between any open software (Maya, web browser) and UE4 while Simulation is running, sometimes the values change on the asset and it starts to oscilate between <-0.6,0.6> or any other s ...

Frequent ensure opening meshes on Mac, locks up AMD machines

UE - Graphics Features - Jun 6, 2017

REGRESSION No, I was able to reproduce the hard lock in 4.16.1. A frequent ensure occurs when opening static or skeletal meshes on Mac. Doesn't reproduce 100% of the time, but I've gotten it about ...

Material slot assignment incorrect after mesh reduction completely removes all triangles from a section

UE - Editor - Content Pipeline - Asset Build - Apr 28, 2022

When mesh reduction results in a section becoming empty, the material slots are incorrectly assigned. e.g. if section 0 gets removed due to it having no triangles after reduction, then its material ...

Cannot paste text into Text Box in HTML5 build

UE - Platform - Mobile - Sep 14, 2017

With HTML 5 Packages you cannot use the windows clipboard to paste things into the text box. This issue does not occur with other builds of the project. This issue does not appear to be a regression ...

Fog Does Not Behave As Expected in Splitscreen

UE - Graphics Features - May 25, 2018

This bug seems to repro very inconsistently for me, but I've seen it affect Atmospheric Fog and Exponential Height Fog, and reproduced in 4.18.3, 4.19.2, and Main CL 4093338. I've attached Config fi ...

When the Initial Position of an Animation Asset is entered outside the expected range, the animation gets stucked and does not refresh.

UE - Anim - Runtime - Mar 18, 2024

The animation gets "corrupted" when the Initial Position value has an invaildad value. In this case, this means that the Initial Position value is outside the range of the duration of the Animation. ...

Imported FBX causes a crash

Tools - Apr 22, 2016

Edit MattK: This seems like more of a cooking issue than an fbx issue. The crash is related to nav collision When adding a FBX import into your project, if you do not close the project out and ope ...