Unreal Engine Issues
Unreal Engine Issues
Crash when attempting to change the parent of a material instance constant through editor scripting
UE - Rendering - Architecture - Materials - Apr 9, 2025The built-in class "UMaterialEditingLibrary" provides various editor scripting functions related to creating and editing materials and material instances. One of these functions, UMaterialEditingLib ...
LevelStreamingPersistence: Crash when streaming in destroyed map actor with persisted properties
UE - World Creation - Worldbuilding Tools - Mar 6, 2026Context The LevelStreamingPersistence plugin can be used to remember and restore properties on actors and components that are part of a streamed level. Saved property values are restored when a lev ...
[CrashReport] UE4Editor_Core!FTaskGraphImplementation::WaitUntilTasksComplete() [taskgraph.cpp:1121]
Tools - Apr 5, 2016This Jira was created from CrashReports submitted by the public due to the high number of occurrences. Descriptions from users are provided below. Error message: Assertion failed: CurrentThreadIfK ...
Static Mesh cooking: Bad mesh description should not crash the cooker
UE - Graphics Tools - Modeling Tools - Mesh Editing - Aug 21, 2023FStaticMeshRenderData::Cache has the assertion: checkf(Owner->IsMeshDescriptionValid(0), TEXT("Bad MeshDescription on %s"), *GetPathNameSafe(Owner)); This assertion can be triggered by data erro ...
[CrashReport] Crash on Mac due to uncaught exception 'NSRangeException' - NSCFConstantString characterAtIndex
UE - Platform - Apple - Jul 27, 2017This is a common and longstanding community crash on Mac. Users have not provided descriptions when they crash, so additional information is currently not available. A log file is attached. Callsta ...
[Enhanced Input] Chord trigger fails when its referenced action lives in a lower-priority IMC
UE - Gameplay - Input - May 18, 2026Summary A UInputTriggerChordAction does not fire when the action it references (the "chording action") is mapped in a different Input Mapping Context with a lower priority than the IMC containing the ...
[CrashReport] Assertion on Mac in FCocoaRunLoopSource
UE - Platform - Apple - Jun 14, 2017This is a common crash among Mac users in 4.16. It is spread out among many separate CrashGroups, with slight variations in Callstack. Some Example CrashGroups [Link Removed] [Link Removed] [Link ...
FEvaluateActorReferenceChannels don't run on GameThread
UE - CAPT - Sequencer - Aug 4, 2026When playing back sequences on a character that is bound users will sometimes run into an ensure from FEvaluateActorReferenceChannels. ...
Ensure condition failed : SkeletalMeshLocation module on scaled SkeletalMesh
UE - Niagara - Jul 14, 2020The message in ensure is below LogOutputDevice: Error: === Handled ensure: === LogOutputDevice: Error: Ensure condition failed: (FMath::Abs(1.f - M.GetScaledAxis(EAxis::X).SizeSquared()) <= (1.e-4 ...
Crash in MaterialInstance when deleting a layer
UE - Graphics Features - May 4, 2021Repro from licensee here - [Link Removed] ...