Trying to open Matinee Editor causes Editor to crash

**I have several other matinees that I can open and edit without a problem but after I tried to create an event in the matinee, the editor will not let me access it. **

Here is the Crash Report:




MachineId:562B7ABA47FC524DE82D21B0A513E04A
EpicAccountId:d0cf1a6bd2f14e0c9f18483aef8762b3

Unknown exception - code 00000001 (first/second chance not available)

"Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.8\Engine\Source\Runtime\Core\Public\Containers\Array.h] [Line: 678]
Arra

UE4Editor_Core!FDebug::AssertFailed() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\private\misc\outputdevice.cpp:355]
UE4Editor_Engine!AMatineeActor::UpdateInterpForParentMovementTracks() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\interpolation.cpp:933]
UE4Editor_Engine!AMatineeActor::SetupCameraCuts() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\interpolation.cpp:972]
UE4Editor_Engine!AMatineeActor::InitInterp() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\interpolation.cpp:879]
UE4Editor_Matinee!FMatinee::InitMatinee() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\matinee\private\matinee.cpp:520]
UE4Editor_Matinee!FMatineeModule::CreateMatinee() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\matinee\private\matineemodule.cpp:48]
UE4Editor_UnrealEd!FEdModeInterpEdit::InitInterpMode() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\unrealed\private\editormodeinterpolation.cpp:136]
UE4Editor_UnrealEd!UEditorEngine::OpenMatinee() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\unrealed\private\editorengine.cpp:3355]
UE4Editor_LevelEditor!TBaseStaticDelegateInstance::ExecuteIfSafe() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:921]
UE4Editor_SceneOutliner!UE4Function_Private::TFunctionRefCaller< const ,void cdecl(SceneOutliner::FActorTreeItem const & ptr64)>::Call() [d:\buildfarm\buildmachine++depot+ue4-releases+4.8\engine\source\runtime\core\public\templates\function.h:193]
UE4Editor_SceneOutliner!SceneOutliner::OnSceneOutlinerItemClicked() [d:\buildfarm\buildmachine
++depot+ue4-releases+4.8\engine\source\editor\sceneoutliner\private\sceneoutlinermodule.cpp:25]
UE4Editor_SceneOutliner!TBaseStaticDelegateInstance cdecl(TSharedRef),TBaseDelegate >::Execute() [d:\buildfarm\buildmachine++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:853]
UE4Editor_SceneOutliner!TBaseStaticDelegateInstance),TBaseDelegate >::ExecuteIfSafe() [d:\buildfarm\buildmachine
++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:919]
UE4Editor_SceneOutliner!TBaseDelegate >::ExecuteIfBound() [d:\buildfarm\buildmachine
++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:519]
UE4Editor_SceneOutliner!SceneOutliner::SSceneOutliner::OnOutlinerTreeSelectionChanged() [d:\buildfarm\buildmachine
++depot+ue4-releases+4.8\engine\source\editor\sceneoutliner\private\ssceneoutliner.cpp:1560]
UE4Editor_SceneOutliner!TBaseSPMethodDelegateInstance<0,SceneOutliner::SSceneOutliner,0,TTypeWrapper cdecl(TSharedPtr,enum ESelectInfo::Type)>::Execute() [d:\buildfarm\buildmachine++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:282]
UE4Editor_SceneOutliner!TBaseSPMethodDelegateInstance<0,SceneOutliner::SSceneOutliner,0,void cdecl(TSharedPtr,enum ESelectInfo::Type)>::ExecuteIfSafe() [d:\buildfarm\buildmachine++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:388]
UE4Editor_SceneOutliner!TBaseDelegate,enum ESelectInfo::Type>::ExecuteIfBound() [d:\buildfarm\buildmachine
++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:519]
UE4Editor_SceneOutliner!SListView >::Private_SignalSelectionChanged() [d:\buildfarm\buildmachine
++depot+ue4-releases+4.8\engine\source\runtime\slate\public\widgets\views\slistview.h:609]
UE4Editor_SceneOutliner!STableRow >::OnMouseButtonUp() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\slate\public\widgets\views\stablerow.h:437]
UE4Editor_SceneOutliner!SceneOutliner::SSceneOutlinerTreeRow::OnMouseButtonUp() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\sceneoutliner\private\soutlinertreeview.cpp:211]
UE4Editor_Slate!::operator()() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4170]
UE4Editor_Slate!FEventRouter::Route >() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:212]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonUpEvent() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4173]
UE4Editor_Slate!FSlateApplication::OnMouseUp() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4133]
UE4Editor_Core!FWindowsApplication::ProcessDeferredMessage() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\private\windows\windowsapplication.cpp:1403]
UE4Editor_Core!FWindowsApplication::DeferMessage() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\private\windows\windowsapplication.cpp:1708]
UE4Editor_Core!FWindowsApplication::ProcessMessage() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\private\windows\windowsapplication.cpp:706]
UE4Editor_Core!FWindowsApplication::AppWndProc() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\private\windows\windowsapplication.cpp:628]
user32
user32
UE4Editor_Core!FWindowsPlatformMisc::PumpMessages() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\private\windows\windowsplatformmisc.cpp:792]
UE4Editor!FEngineLoop::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\launchengineloop.cpp:2323]
UE4Editor!GuardedMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\windows\launchwindows.cpp:200]

I’m also having a similar issue with matinee in 4.9. I have three matinees in my project, with 1 of them being quite large. When I try and update the engine version of the project from 4.7 to 4.9, attempting to edit or play that matinee causes the engine to crash.

Are you referencing the same actor in multiple Matinee’s by any chance?

Not at all. Thankfully I’ve just managed to fix the issue.

The root of the problem was caused by a track we had imported from 3ds Max. Once I’d removed the track from the scene and then removed it from the matinee sequence, I manually activated the track in the level blueprint instead. This allowed me to open matinee and build in 4.9.1. Totally fixed.