Engine crashes when opening behaviour tree

Development Programming & Scripting
1

Fixed up a behaviour tree yesterday. I go to run it today and it’s not working the same. I open the BT and the engine crashes. Engine crashes every time I open the BT.

@MieszkoZ can you take a look please

My crash call stack is below

Access violation - code c0000005 (first/second chance not available)

UE4Editor_BehaviorTreeEditor!UBehaviorTreeGraph::UpdatePinConnectionTypes() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\editor\behaviortreeeditor\private\behaviortreegraph.cpp:193]
UE4Editor_BehaviorTreeEditor!UBehaviorTreeGraph::OnLoaded() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\editor\behaviortreeeditor\private\behaviortreegraph.cpp:165]
UE4Editor_BehaviorTreeEditor!FBehaviorTreeEditor::RestoreBehaviorTree() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\editor\behaviortreeeditor\private\behaviortreeeditor.cpp:281]
UE4Editor_BehaviorTreeEditor!FBehaviorTreeEditorApplicationMode::PostActivateMode() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\editor\behaviortreeeditor\private\behaviortreeeditormodes.cpp:97]
UE4Editor_Kismet!FWorkflowCentricApplication::SetCurrentMode() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\editor\kismet\private\workflowcentricapplication.cpp:72]
UE4Editor_BehaviorTreeEditor!FBehaviorTreeEditor::InitBehaviorTreeEditor() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\editor\behaviortreeeditor\private\behaviortreeeditor.cpp:256]
UE4Editor_BehaviorTreeEditor!FBehaviorTreeEditorModule::CreateBehaviorTreeEditor() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\editor\behaviortreeeditor\private\behaviortreeeditormodule.cpp:126]
UE4Editor_BehaviorTreeEditor!FAssetTypeActions_BehaviorTree::OpenAssetEditor() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\editor\behaviortreeeditor\private\assettypeactions_behaviortree.cpp:49]
UE4Editor_UnrealEd!FAssetEditorManager::OpenEditorForAsset() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\editor\unrealed\private\toolkits\asseteditormanager.cpp:338]
UE4Editor_BehaviorTreeEditor!FAssetTypeActions_Base::AssetsActivated() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\developer\assettools\public\assettypeactions_base.h:41]
UE4Editor_ContentBrowser!SContentBrowser::OnAssetsActivated() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\editor\contentbrowser\private\scontentbrowser.cpp:1768]
UE4Editor_ContentBrowser!TBaseSPMethodDelegateInstance<0,SContentBrowser,0,TTypeWrapper __cdecl(TArray const & __ptr64,enum EAssetTypeActivationMethod::Type)>::Execute() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:321]
UE4Editor_ContentBrowser!TBaseSPMethodDelegateInstance<0,SContentBrowser,0,void __cdecl(TArray const & __ptr64,enum EAssetTypeActivationMethod::Type)>::ExecuteIfSafe() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:428]
UE4Editor_ContentBrowser!TBaseDelegate const & __ptr64,enum EAssetTypeActivationMethod::Type>::ExecuteIfBound() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:608]
UE4Editor_ContentBrowser!SAssetView::OnListMouseButtonDoubleClick() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\editor\contentbrowser\private\sassetview.cpp:3405]
UE4Editor_ContentBrowser!TBaseSPMethodDelegateInstance<0,SAssetView,0,TTypeWrapper __cdecl(TSharedPtr)>::Execute() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:321]
UE4Editor_ContentBrowser!TBaseSPMethodDelegateInstance<0,SAssetView,0,void __cdecl(TSharedPtr)>::ExecuteIfSafe() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:428]
UE4Editor_ContentBrowser!TBaseDelegate >::ExecuteIfBound() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:608]
UE4Editor_ContentBrowser!SListView >::Private_OnItemDoubleClicked() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\slate\public\widgets\views\slistview.h:689]
UE4Editor_ContentBrowser!STableRow >::OnMouseButtonDoubleClick() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\slate\public\widgets\views\stablerow.h:264]
UE4Editor_Slate!::operator()() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4891]
UE4Editor_Slate!FEventRouter::Route >() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:214]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonDoubleClickEvent() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4889]
UE4Editor_Slate!FSlateApplication::OnMouseDoubleClick() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4864]
UE4Editor_Core!FWindowsApplication::ProcessDeferredMessage() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\private\windows\windowsapplication.cpp:1357]
UE4Editor_Core!FWindowsApplication::DeferMessage() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\private\windows\windowsapplication.cpp:1732]
UE4Editor_Core!FWindowsApplication::ProcessMessage() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\private\windows\windowsapplication.cpp:697]
UE4Editor_Core!FWindowsApplication::AppWndProc() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\private\windows\windowsapplication.cpp:619]
user32
user32
UE4Editor_Core!FWindowsPlatformMisc::PumpMessages() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\private\windows\windowsplatformmisc.cpp:884]
UE4Editor!FEngineLoop::Tick() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\launch\private\launchengineloop.cpp:2611]
UE4Editor!GuardedMain() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\launch\private\windows\launchwindows.cpp:200]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:264]
kernel32
ntdll
2

Hello,

I have a few questions to gather more information about the crash:

  • Could you provide the logs from your project’s Saved->Logs folder after the crash occurs?
  • Does the crash happen if you migrate the BT into a clean project and try to open it there?
3

LogsCreatedFromCrash.zip

crash still happens after exporting to a new project

edit: the BT still runs (not like it was last night when it was tested), but it runs without crashing. Only crashes when opening the BT

4

Could you please zip up the affected behavior tree and provide it to me so I can try it on my end in a clean project?

5

After some further investigation, this crash appears to be relating to a corrupted asset. Unfortunately, if you’re not using Source Control, and a copy doesn’t exist in your Saved->Backups folder, there’s not much you can do in the way of recovery. I’d recommend starting the BT from scratch and looking into using source control in the future to avoid asset loss.

Have a great day