Create Session does not work in a packaged game from any project that has used C++

UE - Networking - Dec 28, 2015

After adding C++ to a content-only project, Create Session no longer works in a packaged game. The following warning appears in the log: LogScript:Warning: CreateSession - Invalid or uninitialized ...

[CrashReport] UE4Editor_Engine!FAnimNotifyEvent::IsBranchingPoint() [animtypes.cpp:86]

OLD - Anim - Aug 29, 2017

This is a common crash occurring in the 4.17 release. Users have not provided any descriptions of their actions when the crash occurred. Source Context 72 float FAnimNotifyEvent::GetDurati ...

Blueprint diff tool does not highlight differences when a change is made to a property in a component

UE - Gameplay - Blueprint - Jun 20, 2018

When making changes to a property in a component of a Blueprint, those changes are not highlighted when looking at the changes in the Components section of the Blueprint Diff tool. ...

Indirect lighting samples incorrect if duplicated levels placed in same persistent level

UE - Graphics Features - Aug 29, 2017

Indirect lighting samples were not made correctly when building lighting with umap duplicated via the content browser and registering both source and destination as sublevels in one map. ...

Memory leak when Lumen is disabled but r.MeshCardRepresentation=1

UE - Rendering - Graphics Features - Lumen - Jul 29, 2024

When Lumen is disabled, but the cvar "r.MeshCardRepresentation" is set to 1, Lumen will continuously enqueue object removal from the Lumen Scene, without ever emptying the array of primitives to rem ...

Copying a grouped MaterialInstanceParameterDetail property that has spaces on it's name does not enclose it in double quotes, and later pasting won't work as expected

UE - Rendering - Architecture - Materials - Aug 24, 2025

Copying a grouped MaterialInstanceParameterDetail property that has spaces on it's name does not enclose it in double quotes, and later pasting won't work as expected. The licensee noticed this in a ...

Regression - Nested scene component subobjects are no longer being registered when the owning scene component is added to an existing Actor instance as an instanced component.

UE - Gameplay - Components - Nov 16, 2016

This is a regression that was introduced with changes made to address issues with native vs. non-native component registration at Blueprint construction time ([Link Removed]). Prior to those change ...

Editor 'Build All Levels' discards Volumetrics Lightmaps in persistent level

UE - Graphics Features - May 14, 2025

Building the level or lightmaps can clear the volumetric lightmap. In 5.5, this requires you to perform a full build, or a lighting only build with a BSP brush in the scene. In 5.6, all level build ...