[CrashReport] Mac crash - UE4Editor-Slate.dylib!PrepassWindowAndChildren(TSharedRef<SWindow, (ESPMode)0>)

UE - Platform - Apple - Oct 27, 2017

This Mac crash originally occurred in 4.15 around March 2017, then decreased in frequency during 4.16 and 4.17. It may be starting to trend again in 4.18. There is one record of this occurring in 4 ...

CRITICAL: Regression: CRASH: SHOOTERGAME: Client crashes when using ServerTravel command

UE - Networking - Sep 17, 2014

Update (5/4/15): New repro steps using Main (//depot/UE4/Promotable-CL-2535351): 1. Create a new Blueprint project 2. Create 3 new Levels: MainMenu, Lobby, and Level 3. Create 3 new GameModes: Main ...

Bloated instruction counts in the material editor causing long compiles

UE - Graphics Features - Apr 17, 2019

artists are dealing with greatly increased iteration times due to long shader compiles when working in the material editor. This has regressed over time as we add more features to the point were wor ...

HTTP If-None-Match response code is incorrect on Macintosh

Tools - Sep 22, 2016

Macintosh implementation for HTTP requests handle If-None-Match against ETags differently than Windows implementation. ...

Crash when attempting to change the parent of a material instance constant through editor scripting

UE - Rendering - Architecture - Materials - Apr 9, 2025

The built-in class "UMaterialEditingLibrary" provides various editor scripting functions related to creating and editing materials and material instances. One of these functions, UMaterialEditingLib ...

DLC Package content isn't recognized when using RequestAsyncLoad

UE - Foundation - Core - May 24, 2016

Attempting to load dlc assets with RequestAsyncLoad function results in the assets not being recognized. ...

Changing the state of a PrimitiveComponent->BodyInstance while SetSimulatePhysics(false) updates the game thread but does not update the physics behavior

UE - Simulation - Physics - Nov 21, 2024

Changing the state of a PrimitiveComponent->BodyInstance while SetSimulatePhysics(false) updates the game thread but does not update the physics behavior. In the repro project provided (see addl in ...

iOS Shipping Build using std::thread crashes on launch

UE - Platform - Mobile - Jun 2, 2017

A user is reporting that using the following code in a GameMode class causes shipping iOS packages to crash on launch:void ANOGSSDKGameModeBase::StartPlay() { std::thread([](){ std::clog << "THRE ...

Updates to DesiredFocusWidget for a UserWidget are not propagated to existing instances of it inside the WidgetTree of other widgets

UE - Editor - UI Systems - Nov 17, 2025

This issue has been reproduced in UE 5.3 to 5.7 and source versions. A repro project is available. Below are the findings from an initial investigation of the problem. Normally, when a UserWidget p ...

Fix up IOS errors calling UI API from non-UI threads

UE - Platform - Apple - Jul 27, 2020