Unreal Engine Issues
Unreal Engine Issues
"FVector contains NaN" on packaged builds for Debug configuration
UE - Rendering - Features - Lumen - May 6, 2022Customer Provided Description:This was experienced in UE 5.01 - custom installed engine (No changes to UE code, simply added the Debug build configuration, see the following command): "c:%ue_dire ...
Skeletal mesh LODs never stream up under SSAM: FSkeletalMeshSceneProxy caches ForceStreamedLOD and is never re-gathered
UE - Engine Scaling - Streaming - Jul 29, 2026UE 5.8, cooked build, SSAM enabled (s.StreamableAssets.UseSimpleStreamableAssetManager=1, required by FastGeo). Symptom: characters spawn at a crude LOD and can never stream up for the lifetime of ...
Update Mesh Section incorrectly sets vertex colors for a Procedural Mesh
UE - Graphics Tools - Modeling Tools - Jun 21, 2022This is a regression tested in //UE4/Release-4.27 CL#18319896 Update Mesh Section incorrectly sets vertex colors for a Procedural Mesh. The closer a colors R, G, or B value is to 1.0 or 0.0 the mor ...
DynamicEntryBox with EntryBoxType Radial is stacking Entries if SectorCentralAngle is multiple of 360.0f and DistributeItemsEvenly is enabled
UE - AI Workflows - UI Systems - May 27, 2025DynamicEntryBox with EntryBoxType Radial is stacking Entries if SectorCentralAngle is multiple of 360.0f and DistributeItemsEvenly is enabled. The licensee has provided an analysis: On void SRadia ...
Right-clicking in the Event Graph of a second Blueprint created using Create Blueprint Using This... will crash the editor
UE - Gameplay - Blueprint - Dec 9, 2014Right-clicking in the Event Graph of a second Blueprint created using Create Blueprint Using This... will crash the editor. Crash Report: [Link Removed] Call Stack:<unknown module>! KERNELBASE!Rai ...
Crash when spawning actor with no viewport initialized
UE - Editor - Nov 22, 2023If an attempt to spawn an actor is made before the Level Editor Viewport is fully initialized (i.e. before it has had a chance to get rendered at least once), and that actor has no specific Factory ...
[CrashReport] Linux crash - FMonitoredProcess::Launch()
UE - Platform - Linux - Sep 14, 2017This is an infrequent Linux crash occurring in 4.17.1. Callstack from Log[2017.09.06-15.26.30:028][666]LogLinux: Error: appError called: Assertion failed: Assertion failed: [File:/home/***/.local/ ...
Error when exporting OBJ unattended
UE - Editor - Content Pipeline - Import and Export - Dec 1, 2020When doing an unattended OBJ export with python. The export will fail and give the atteched callstack. ...
UCS continuously runs while a blueprint's thumbnail in content browser is focused
UE - Editor - Content Pipeline - Content Browser - May 18, 2016Blueprints with a mesh call the UCS continuously when focusing the thumbnail in the content browser. This is easily visible with a Print String in the UCS causing log spam. This does not occur in ...
Importing Camera FBX into a sequence can crash with a headless editor
UE - Anim - Sequencer - Mar 19, 2021In a headless editor instance we will not be able to send toasts to the user, and we should not notify slate. The Sequencer Tools function library calls MovieSceneToolHelpers::ImportFBXCameraToExist ...