Unreal Engine Issues
Unreal Engine Issues
Assertion failed: (Index >= 0) & (Index < ArrayNum) when importing large Alembic file
UE - Editor - Content Pipeline - Datasmith - Importer - May 3, 2022Regression testing done on //UE4/Release-4.27.2 CL-18427296 and this issue did occur. [Link Removed] [Link Removed] Below is snips of customers description and proposed workaround:Importing alembi ...
[UDN - 00707230] DetailLayoutHelpers ensure when using VisibleAnywhere Instanced properties
UE - Editor - Verse Class Editor - Jan 11, 2024From UDN Description Hello, there's an ensure that's firing in `DetailLayoutHelpers.cpp#137`: [Start code block] ensure(PropertyNodeMap.ParentProperty == CurObjectNode); [End code block]when ...
[CrashReport] Mac crash - TArray<FDeferredMacEvent, FDefaultAllocator>::ResizeGrow
UE - Platform - Apple - Sep 14, 2017This is a somewhat common crash on Mac that has affected users since 4.16. Users have not provided any descriptions of their actions when the crash occurred. Callstack from Log [2017.09.08-05.17. ...
StateTree: While editing State Parameters or exposed properties of a Condition/Task, an ensure() fires when editing inputs of a Property Function bound to an array element
UE - AI - StateTree - Mar 5, 2026Consider an array property that can be edited in the StateTree editor. This can be a State Parameter or an exposed property of a Condition or Task, for example. Each element of the array can be boun ...
Wrong WPO motion vectors due to Periodic World Space node
UE - Rendering - Graphics Features - May 13, 2026We've noticed smearing in grass due to wrong motion vectors. This appears to be caused by lack of previous frame support in the periodic world space node. This is how we fixed it: In MaterialTempl ...
Virtual Memory leak when using specific rendering settings in the template project
UE - Rendering - Architecture - RHI - Dec 20, 2025When a project is run with these settings in a template project, untracked virtual memory increases. Cvars r.GBufferFormat 3 r.Lumen.TraceMeshSDFs 1 r.Lumen.TranslucencyReflections.FrontLayer.Enab ...
[CrashReport] UE4Editor_CoreUObject!UObjectPropertyBase::Identical() [propertybaseobject.cpp:60]
UE - Foundation - Cpp Tools - Hot Reload - Nov 17, 2016This Jira was created from CrashReports submitted by the public due to the high number of occurrences. Error message: Access violation - code c0000005 (first/second chance not available) Source C ...
User-defined InstancedStaticMeshComponent subclass misbehave in SCS Editor
UE - Framework - Blueprint Editor - Oct 13, 2025Context Users can create InstancedStaticMeshComponent (ISMC) (blueprint) subclasses. Any ISMC class can be added to an actor blueprint. When a mesh is selected and transforms are added to the Insta ...
Backwards-compatibility broken for the CDOs of Python-generated Unreal Types because of missing redirectors
UE - Editor - Feb 11, 2025Previously, all Unreal Types generated by python scripts would be created inside package "/Engine/PythonTypes". This was changed by [CL 32478991 in ue5-main branch], which meant to "remove the restr ...
[CrashReport] Crash on Mac - UE4Editor-SlateCore.dylib!SWindow::IsVisible()
UE - Platform - Apple - Jun 23, 2017This is a common crash on Mac in the 4.16 release, and has occurred with low frequency since at least 4.11. Users have not provided any descriptions, so additional information is currently unknown. ...