Unreal Engine Issues
Unreal Engine Issues
Navmesh doesn't work in a Packaged Build if it was placed in a Sublevel
UE - AI - Oct 19, 2018Once packaged, a persistent level is unable to create navmesh data properly if the navmesh bounds volumes are only present in its sublevels. The issue can be traced to the UNavigationSystemV1::IsThe ...
If use Remove Unused Bones from Skeleton, PoseAsset of the skeleton will be broken
UE - Anim - Runtime - Jul 10, 2019If user execute "Remove Unused Bones from Skeleton" on Skeleton where PoseAsset exists, the index held in FPoseData :: TrackToBufferIndex in PoseAsset will not be corrected, and it will refer to the ...
When painting on a landscape with edit layers, there are UV distortions happening across the boundaries of paint layers when material is using SetMaterialAttributes
UE - Graphics Tools - Terrain - Landscape - Mar 10, 2025Context Landscape Edit Layers enables users to paint landscapes using non-destructive layers, and can add multiple layers to the landscape that can be edited independently from each other. Problem ...
Division by zero causing NaN/Inf on USkeletalMeshComponent::UpdateRigidBodyScaling() when setting scale to zero and back
UE - Runtime - Simulation - Feb 11, 2026Up to UE 5.5, skeletal mesh physics did not get updated when the component's scale changed. This was improved on January 2025 with CL 39190335, which addressed [Link Removed] ...
SplineMeshComponent resources leak
UE - Rendering - Features - Aug 3, 2026A race condition occurs in the InitSplineVertexFactory_Internal }}function call, which is distributed across multiple threads. This causes {{FSplineMeshVertexFactory to be instantiated multiple time ...
[CrashReport] Assertion failed: NewWorld | UE4Editor_Engine!UEngine::LoadMap()
UE - Gameplay - Nov 2, 2017This is a common and longstanding crash that has occurred since at least 4.15. Originally this was being tracked under [Link Removed] due to sharing the same callstack, but that had specific repro ...
Crash when making Android package in SlateTextShaper.cpp
UE - Editor - UI Systems - Slate - Apr 7, 2020Crash when outputting garbled text when creating Android package. It did not occur in my colleague's environment using English OS, but occurred in my environment using Japanese OS. This issue should ...
Incremental Cooks: Add dependencies on files loaded during Load/Save of the package
UE - Core - Data Pipeline - Cooker - Oct 19, 2022Iterative and Incremental cooking are supposed to recook packages when their "inputs" change. Most of the time inputs are the package file itself and the other package files on which it has dependen ...
Mesh Space Additive behave differently for non-animated bones and extra bones on a target skeleton
UE - Runtime - Animation - Dec 6, 2023Typically, non-animated bones behave the same way as extra bones on a target skeleton. However, it appears that this isn't the case for mesh space additive sequences. When a bone is present on th ...
Crash when Live Coding is triggered after engine source edits Blueprints using ChildActorComponent
UE - Framework - Blueprint - Nov 28, 2025After editing engine source files and triggering Live Coding, derived Blueprints that inherit from a Blueprint containing a ChildActorComponent cause UChildActorComponent::Serialize to run on a Live ...