[CrashReport] UE4Editor_Engine!FUniformExpressionSet::CreateUniformBuffer() [materialuniformexpressions.cpp:354]

UE - Graphics Features - Nov 30, 2015

Error Message - Assertion failed: !Value || Value->IsValidLowLevel() [File[Image Removed]:\BuildFarm\buildmachine_++depot+UE4-Releases+4.10\Engine\Source\Runtime\Engine\Private\Materials\MaterialU ...

[CrashReport] Mac crash - libobjc.A.dylib!objc_retain() [UnknownFile]

UE - Platform - Apple - Nov 10, 2017

This is a longstanding but low frequency Mac crash. User DescriptionsChanging camera shake values and testing in a new editor window Callstack from Log[2017.11.09-19.23.22:392][ 63]LogMaterial: Mi ...

Crash when attempting to change the parent of a material instance constant through editor scripting

UE - Rendering - Architecture - Materials - Apr 9, 2025

The 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, 2026

Context 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, 2016

This 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, 2023

FStaticMeshRenderData::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, 2017

This 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, 2026

Summary 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, 2017

This 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 ...

Ensure condition failed : SkeletalMeshLocation module on scaled SkeletalMesh

UE - Niagara - Jul 14, 2020

The 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 ...