Destroying a welded actor is causing an Array index out of bounds crash on 5.6

UE - Runtime - Simulation - Jul 30, 2025

Destroying a welded actor is causing an Array index out of bounds crash on 5.6. The licensee has provided a repro project that reliably causes a crash whenever the spawned actor is destroyed. There ...

Crash when switching from Lumen visualization to raytracing visualization

UE - Rendering - Features - Mar 27, 2026

When switching from Lumen visualization to raytracing visualization via the console, the editor can crash to desktop. The crash appears to happen deep within the driver libraries, and does not trig ...

HLOD Build crashing when building nanite for mesh with 2 material having the same parameters

UE - Engine Scaling - Streaming - HLOD - Dec 2, 2023

From Licensee: Catching the exception with debugger allowed us to find a list of materials on the hlod mesh on which the error occured and we were then able to link it to one of our meshes causing ...

Adding parent constraint to control rig in shot crashes the editor

UE - ACT Character - Anim in Engine - Mar 10, 2023

Adding a constraint to a control rig in a subsequence will crash the editor. ...

Crash when changing details of an animation in an Animation Composite

UE - Runtime - Animation - Jun 7, 2022

This is a regression tested in //UE4/Release-4.27 CL#18319896 Fatal error is thrown and the Editor crashes when changing details of an animation in an Animation Composite. ...

Adding "_API" specifier to FMovieSceneTrackEditor results in linker errors

UE - Anim - Sequencer - Feb 7, 2017

Unable to add API specifier to FMovieSceneTrackEditor, results in compile errors (pasted in the callstack field) ...

Renaming actors between levels during PIE causes issues

UE - Engine Scaling - Streaming - OFPA - Dec 4, 2023

When renaming actors during PIE the actor generates a new, non memory/temporary, actor package underneath the PIE world- this is then causing checks in EnumerateMemoryAssetsHelper (in AssetRegistry. ...

Crash when opening a texture or editing its properties after stopping a preview in the material editor

UE - Rendering - Architecture - Materials - Sep 5, 2025

When a texture asset has certain properties edited, its PostEditChangeProperty() method calls to UTexture::NotifyMaterials(), which triggers a recompilation of materials that reference it in their m ...

Compiling twice then pressing play/stop after creating a c++ Game Instance causes a crash

UE - Core - Cpp Tools - Jan 24, 2022

This is not a regression. After creating a C++ based Game Instance the Editor crashes if you compile twice then play and stop. ...

GAS PlayMontageAndWait: Server applies root motion with wrong scale at last montage tick

UE - Gameplay - Gameplay Ability System - Apr 3, 2024

User reported: when playing an AnimMontage via GameplayAbility with the PlayMontageAndWait ability task that has a custom value for AnimRootMotionTranslationScale, (dedicated) servers can apply an i ...