When using 'r.VT.SplitPhysicalPoolSize 64' with nanite meshes, mesh painting does not update in real time (only updates after stroke finished), duplicates mesh painting across separate instances of a mesh, and sometimes doesn't show up in PIE.

UE - Rendering Architecture - Mar 3, 2025

When using Mesh Painting on nanite meshes in 5.5 with 'r.VT.SplitPhysicalPoolSize' set to non-zero values (e.g. 16, 64), several issues occur, such as: 1. Painting doesn't update in real time (only ...

When multiple actors are selected, they have different undo behavior in the details panel

UE - Editor - Workflow Systems - Nov 15, 2021

When the text in spinbox has focus, it doesn't get the change notification externally. It may also be worth noting that ctrl z or ctrl y also do not get bubbled up to undo the text box values. It a ...

Compiler error after changing the class in a Spawn Actor from Class node, undoing with Ctrl + Z, refreshing the node, and reconnecting exposed variables

UE - Gameplay - Blueprint - May 26, 2015

Compiler error after changing the class in a Spawn Actor from Class node, undoing with Ctrl + Z, refreshing the node, and reconnecting exposed variables. "Error Internal compiler error inside Creat ...

In 5.6, bWarningsAsErrors does not work with clang

UE - Foundation - Cpp Tools - UnrealBuildTool - Sep 20, 2025

In 5.6, many warnings and errors specify their command line arguments to the compiler with these new C# attributes:    [WarningsClangToolChain(["-Wno-date-time"], ["-Wdate-time", "-Wno-error=date-ti ...

UAT searches wrong root folder for include paths specified in .Build.cs

UE - Foundation - Cpp Tools - Automation Tool - Jun 21, 2018

When running the BuildPlugin command on a plugin in 4.20 preview 3, UAT is not detecting the correct root folder for the relative include paths specified in a module's .Build.cs. Expected: UAT is a ...

Static light contained in a blueprint will need lighting rebuilt each time the project is reopened

UE - Gameplay - Jun 29, 2017

Static light contained in a blueprint will need lighting rebuilt each time the project is reopened. This only seems to occur for a static light that is parented to a static mesh and then that static ...

Unreal Editor 5.4.4 crash when reproducing a LevelSequence in loop while PIE.

UE - Anim - Sequencer - Sep 9, 2024

A crash inside Unreal Engine Editor version 5.4.4 occurs when reproducing a Level Sequence while in PIE. This issue is a regression. It only crashes in version 5.4.4. It was working correctly in ver ...

[CrashReport] Assertion failed: !PinRef->bWasTrashed | UEdGraphPin::SerializePin()

UE - Gameplay - Blueprint - Aug 29, 2017

This is a common and longstanding crash that has occurred since at least 4.15 and affected nearly 500 users. The CrashGroup was previously linked to [Link Removed], but that had specific repro step ...

Second UVs wiped when using Merge Actors Tool

UE - World Creation - Worldbuilding Tools - HLOD - Jan 26, 2017

The merge actor tool no longer saves additional UVs used for the merged mesh. This was not the case in 4.13, but in 4.14 and later this information is no longer present. Also worth noting is that i ...

Control Rig: crashes when compiling after rearranging input pins in an array in Example Rig Unit

OLD - Anim - Aug 20, 2019

The crash doesn't occur every time, but it will happen within 3 swap and compiles in my experience. I got multiple different callstacks when I cause the crash using the reproduction steps (they are ...