Steps to Reproduce
  1. Create a level with empty open world template
  2. Save the level (ex. /Game/Maps/NewMap)
  3. Place a cube in the level
  4. Right click on the cube and then click Level > Create Level Instance
  5. Press Ok Button in the dialog
  6. Create new folder with the same name as the level (ex. /Game/Maps/NewMap/)
  7. Save the level instance in the folder (ex. /Game/Maps/NewMap/LI_Cube)

Result:

Editor crushes with the following log : 

LogLoad:  - World /Game/UDN/NewMap/CI_Cube.CI_Cube
LogLoad: Error: Printing reference chains leading to World /Game/UDN/NewMap/CI_Cube.CI_Cube: 
LogReferenceChain: (PendingKill) World /Game/UDN/NewMap/CI_Cube.CI_Cube is not currently reachable.
LogLoad: Error: Old World /Game/UDN/NewMap/CI_Cube.CI_Cube not cleaned up by GC! However it's not referenced by any object. It may have a flag set that's preventing it from being destroyed (see log for details):

LogOutputDevice: Warning: 

Script Stack (0 frames) :

Fatal error: [File:D:\dev\UnrealEngine-5.1.0\Engine\Source\Runtime\Engine\Private\UnrealEngine.cpp] [Line: 15915] 
Fatal world leaks detected. Logging first error, check logs for additional information

It also crashes when trying to reopen the persistent level after restarting the editor. logs are : 

Assertion failed: !Level || (Level == ActorLevel) [File:D:\dev\UnrealEngine-5.1.0\Engine\Source\Runtime\Engine\Private\WorldPartition\WorldPartitionHandle.cpp] [Line: 132] 

 

Callstack
UnrealEditor-Engine-Win64-Debug.dll!<lambda_ac64aa3018dbc9ef5cbe1ea86ad0bec6>::operator()<FLogCategoryLogLoad,wchar_t [91],wchar_t const *>(const FLogCategoryLogLoad & LCategoryName, const wchar_t[91] & LFormat, const wchar_t * const & <UE_LOG_Args_0>) Line 15914	C++
UnrealEditor-Engine-Win64-Debug.dll!DispatchCheckVerify<void,<lambda_ac64aa3018dbc9ef5cbe1ea86ad0bec6>,FLogCategoryLogLoad,wchar_t [91],wchar_t const *>(UEngine::FindAndPrintStaleReferencesToObjects::__l111::<lambda_ac64aa3018dbc9ef5cbe1ea86ad0bec6> && Inner, const FLogCategoryLogLoad & <Args_0>, const wchar_t[91] & <Args_1>, const wchar_t * const & <Args_2>) Line 172	C++
UnrealEditor-Engine-Win64-Debug.dll!UEngine::FindAndPrintStaleReferencesToObjects(TArrayView<UObject * const,int> ObjectsToFindReferencesTo, EPrintStaleReferencesOptions Options) Line 15918	C++
UnrealEditor-Engine-Win64-Debug.dll!UEngine::FindAndPrintStaleReferencesToObject(UObject * ObjectToFindReferencesTo, EPrintStaleReferencesOptions Options) Line 15773	C++
UnrealEditor-UnrealEd-Win64-Debug.dll!UEditorLevelUtils::RemoveLevelsFromWorld::__l2::<lambda>(const TArray<FName,TSizedDefaultAllocator<32>> & PackageNames, EPrintStaleReferencesOptions Options) Line 896	C++
UnrealEditor-UnrealEd-Win64-Debug.dll!UEditorLevelUtils::RemoveLevelsFromWorld(TArray<ULevel *,TSizedDefaultAllocator<32>> InLevels, bool bClearSelection, bool bResetTransBuffer) Line 910	C++
UnrealEditor-Engine-Win64-Debug.dll!ULevelInstanceSubsystem::RemoveLevelsFromWorld(const TArray<ULevel *,TSizedDefaultAllocator<32>> & InLevels, bool bResetTrans) Line 1491	C++
UnrealEditor-Engine-Win64-Debug.dll!ULevelStreamingLevelInstanceEditor::Unload(ULevelStreamingLevelInstanceEditor * LevelStreaming) Line 129	C++
UnrealEditor-Engine-Win64-Debug.dll!ULevelInstanceSubsystem::FLevelInstanceEdit::~FLevelInstanceEdit() Line 1731	C++
[External Code]	
UnrealEditor-Engine-Win64-Debug.dll!ULevelInstanceSubsystem::ResetEdit(TUniquePtr<ULevelInstanceSubsystem::FLevelInstanceEdit,TDefaultDelete<ULevelInstanceSubsystem::FLevelInstanceEdit>> & InLevelInstanceEdit) Line 400	C++
UnrealEditor-Engine-Win64-Debug.dll!ULevelInstanceSubsystem::CommitLevelInstanceInternal(TUniquePtr<ULevelInstanceSubsystem::FLevelInstanceEdit,TDefaultDelete<ULevelInstanceSubsystem::FLevelInstanceEdit>> & InLevelInstanceEdit, bool bDiscardEdits, bool bDiscardOnFailure, TSet<FName,DefaultKeyFuncs<FName,0>,FDefaultSetAllocator> * DirtyPackages) Line 2157	C++
UnrealEditor-Engine-Win64-Debug.dll!ULevelInstanceSubsystem::CreateLevelInstanceFrom(const TArray<AActor *,TSizedDefaultAllocator<32>> & ActorsToMove, const FNewLevelInstanceParams & CreationParams) Line 1225	C++
UnrealEditor-LevelInstanceEditor-Win64-Debug.dll!LevelInstanceMenuUtils::CreateLevelInstanceFromSelection(ULevelInstanceSubsystem * LevelInstanceSubsystem, ELevelInstanceCreationType CreationType) Line 330	C++
UnrealEditor-LevelInstanceEditor-Win64-Debug.dll!UE::Core::Private::Tuple::TTupleBase<TIntegerSequence<unsigned int,0,1>,ULevelInstanceSubsystem *,enum ELevelInstanceCreationType>::ApplyAfter<void (__cdecl*const &)(ULevelInstanceSubsystem *,enum ELevelInstanceCreationType)>(void(*)(ULevelInstanceSubsystem *, ELevelInstanceCreationType) & Func) Line 327	C++
UnrealEditor-LevelInstanceEditor-Win64-Debug.dll!TBaseStaticDelegateInstance<void __cdecl(void),FDefaultDelegateUserPolicy,ULevelInstanceSubsystem *,enum ELevelInstanceCreationType>::ExecuteIfSafe() Line 739	C++
UnrealEditor-Slate-Win64-Debug.dll!TDelegate<void __cdecl(void),FDefaultDelegateUserPolicy>::ExecuteIfBound<void,0>() Line 639	C++
UnrealEditor-Slate-Win64-Debug.dll!SMenuEntryBlock::OnClicked(bool bCheckBoxClicked) Line 1157	C++
UnrealEditor-Slate-Win64-Debug.dll!SMenuEntryBlock::OnMenuItemButtonClicked() Line 1108	C++
UnrealEditor-Slate-Win64-Debug.dll!UE::Core::Private::Tuple::TTupleBase<TIntegerSequence<unsigned int>>::ApplyAfter<FReply (__cdecl SMenuEntryBlock::*const &)(void),SMenuEntryBlock * &>(FReply(SMenuEntryBlock::*)() & Func, SMenuEntryBlock * & <Args_0>) Line 327	C++
UnrealEditor-Slate-Win64-Debug.dll!TBaseSPMethodDelegateInstance<0,SMenuEntryBlock,1,FReply __cdecl(void),FDefaultDelegateUserPolicy>::Execute() Line 295	C++
UnrealEditor-Slate-Win64-Debug.dll!SButton::ExecuteOnClick() Line 465	C++
UnrealEditor-Slate-Win64-Debug.dll!SButton::OnMouseButtonUp(const FGeometry & MyGeometry, const FPointerEvent & MouseEvent) Line 390	C++
UnrealEditor-Slate-Win64-Debug.dll!SMenuEntryButton::OnMouseButtonUp(const FGeometry & MyGeometry, const FPointerEvent & MouseEvent) Line 431	C++
UnrealEditor-Slate-Win64-Debug.dll!FSlateApplication::RoutePointerUpEvent::__l8::<lambda>(const FArrangedWidget & TargetWidget, const FPointerEvent & Event) Line 5046	C++
UnrealEditor-Slate-Win64-Debug.dll!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,FReply <lambda>(const FArrangedWidget &, const FPointerEvent &)>(FSlateApplication * ThisApplication, FEventRouter::FToLeafmostPolicy RoutingPolicy, FPointerEvent EventCopy, const FSlateApplication::RoutePointerUpEvent::__l8::FReply <lambda>(const FArrangedWidget &, const FPointerEvent &) & Lambda, ESlateDebuggingInputEvent DebuggingInputEvent) Line 412	C++
UnrealEditor-Slate-Win64-Debug.dll!FSlateApplication::RoutePointerUpEvent(const FWidgetPath & WidgetsUnderPointer, const FPointerEvent & PointerEvent) Line 5032	C++
UnrealEditor-Slate-Win64-Debug.dll!FSlateApplication::ProcessMouseButtonUpEvent(const FPointerEvent & MouseEvent) Line 5601	C++
UnrealEditor-Slate-Win64-Debug.dll!FSlateApplication::OnMouseUp(const EMouseButtons::Type Button, const UE::Math::TVector2<double> CursorPos) Line 5566	C++
UnrealEditor-ApplicationCore-Win64-Debug.dll!FWindowsApplication::ProcessDeferredMessage(const FDeferredWindowsMessage & DeferredMessage) Line 2219	C++
UnrealEditor-ApplicationCore-Win64-Debug.dll!FWindowsApplication::DeferMessage(TSharedPtr<FWindowsWindow,1> & NativeWindow, HWND__ * InHWnd, unsigned int InMessage, unsigned __int64 InWParam, __int64 InLParam, int MouseX, int MouseY, unsigned int RawInputFlags) Line 2726	C++
UnrealEditor-ApplicationCore-Win64-Debug.dll!FWindowsApplication::ProcessMessage(HWND__ * hwnd, unsigned int msg, unsigned __int64 wParam, __int64 lParam) Line 1089	C++
UnrealEditor-ApplicationCore-Win64-Debug.dll!WindowsApplication_WndProc(HWND__ * hwnd, unsigned int msg, unsigned __int64 wParam, __int64 lParam) Line 919	C++
UnrealEditor-ApplicationCore-Win64-Debug.dll!FWindowsApplication::AppWndProc(HWND__ * hwnd, unsigned int msg, unsigned __int64 wParam, __int64 lParam) Line 925	C++
[External Code]	
UnrealEditor-ApplicationCore-Win64-Debug.dll!WinPumpMessages() Line 114	C++
UnrealEditor-ApplicationCore-Win64-Debug.dll!FWindowsPlatformApplicationMisc::PumpMessages(bool bFromMainLoop) Line 145	C++
UnrealEditor-Win64-Debug.exe!FEngineLoop::Tick() Line 5291	C++
UnrealEditor-Win64-Debug.exe!EngineTick() Line 67	C++
UnrealEditor-Win64-Debug.exe!GuardedMain(const wchar_t * CmdLine) Line 205	C++
UnrealEditor-Win64-Debug.exe!LaunchWindowsStartup(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow, const wchar_t * CmdLine) Line 233	C++
UnrealEditor-Win64-Debug.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * pCmdLine, int nCmdShow) Line 282	C++

Reopen the persistent level after restarting editor

UnrealEditor-Engine-Win64-Debug.dll!FWorldPartitionLoadingContext::FDeferred::{dtor}::__l8::<lambda>(TArray<AActor *,TSizedDefaultAllocator<32>> & ActorList, const TSet<FWorldPartitionActorDesc *,DefaultKeyFuncs<FWorldPartitionActorDesc *,0>,FDefaultSetAllocator> & SourceList) Line 132	C++
UnrealEditor-Engine-Win64-Debug.dll!FWorldPartitionLoadingContext::FDeferred::~FDeferred() Line 145	C++
UnrealEditor-Engine-Win64-Debug.dll!IWorldPartitionActorLoaderInterface::ILoaderAdapter::RefreshLoadedState() Line 224	C++
UnrealEditor-Engine-Win64-Debug.dll!IWorldPartitionActorLoaderInterface::ILoaderAdapter::Load() Line 46	C++
UnrealEditor-Engine-Win64-Debug.dll!UWorldPartition::Initialize(UWorld * InWorld, const UE::Math::TTransform<double> & InTransform) Line 607	C++
UnrealEditor-Engine-Win64-Debug.dll!ULevel::OnLevelLoaded() Line 2984	C++
UnrealEditor-Engine-Win64-Debug.dll!UWorld::InitWorld(const UWorld::InitializationValues IVS) Line 1977	C++
UnrealEditor-UnrealEd-Win64-Debug.dll!UEditorEngine::Map_Load(const wchar_t * Str, FOutputDevice & Ar) Line 2786	C++
UnrealEditor-UnrealEd-Win64-Debug.dll!UEditorEngine::HandleMapCommand(const wchar_t * Str, FOutputDevice & Ar, UWorld * InWorld) Line 6232	C++
UnrealEditor-UnrealEd-Win64-Debug.dll!UEditorEngine::Exec(UWorld * InWorld, const wchar_t * Stream, FOutputDevice & Ar) Line 5749	C++
UnrealEditor-UnrealEd-Win64-Debug.dll!UUnrealEdEngine::Exec(UWorld * InWorld, const wchar_t * Stream, FOutputDevice & Ar) Line 659	C++
UnrealEditor-UnrealEd-Win64-Debug.dll!FEditorFileUtils::LoadMap(const FString & InFilename, bool LoadAsTemplate, const bool bShowProgress) Line 2849	C++
UnrealEditor-AssetTools-Win64-Debug.dll!FAssetTypeActions_World::OpenAssetEditor(const TArray<UObject *,TSizedDefaultAllocator<32>> & InObjects, TSharedPtr<IToolkitHost,1> EditWithinLevelEditor) Line 46	C++
UnrealEditor-UnrealEd-Win64-Debug.dll!UAssetEditorSubsystem::OpenEditorForAsset(UObject * Asset, const EToolkitMode::Type ToolkitMode, TSharedPtr<IToolkitHost,1> OpenedFromLevelEditor, const bool bShowProgressWindow) Line 402	C++
UnrealEditor-UnrealEd-Win64-Debug.dll!UAssetEditorSubsystem::OpenEditorForAssets_Advanced(const TArray<UObject *,TSizedDefaultAllocator<32>> & InAssets, const EToolkitMode::Type ToolkitMode, TSharedPtr<IToolkitHost,1> OpenedFromLevelEditor) Line 476	C++
UnrealEditor-UnrealEd-Win64-Debug.dll!UAssetEditorSubsystem::OpenEditorForAssets(const TArray<UObject *,TSizedDefaultAllocator<32>> & Assets) Line 592	C++
UnrealEditor-ContentBrowserAssetDataSource-Win64-Debug.dll!ContentBrowserAssetData::EditOrPreviewAssetFileItems(TArrayView<TSharedRef<FContentBrowserAssetFileItemDataPayload const ,1> const ,int> InAssetPayloads, const bool bIsPreview) Line 288	C++
UnrealEditor-ContentBrowserAssetDataSource-Win64-Debug.dll!ContentBrowserAssetData::EditOrPreviewItems(IAssetTools * InAssetTools, const UContentBrowserDataSource * InOwnerDataSource, TArrayView<FContentBrowserItemData const ,int> InItems, const bool bIsPreview) Line 308	C++
UnrealEditor-ContentBrowserAssetDataSource-Win64-Debug.dll!ContentBrowserAssetData::EditItems(IAssetTools * InAssetTools, const UContentBrowserDataSource * InOwnerDataSource, TArrayView<FContentBrowserItemData const ,int> InItems) Line 314	C++
UnrealEditor-ContentBrowserAssetDataSource-Win64-Debug.dll!UContentBrowserAssetDataSource::BulkEditItems(TArrayView<FContentBrowserItemData const ,int> InItems) Line 1238	C++
UnrealEditor-ContentBrowser-Win64-Debug.dll!SContentBrowser::OnItemsActivated(TArrayView<FContentBrowserItem const ,int> ActivatedItems, EAssetTypeActivationMethod::Type ActivationMethod) Line 3020	C++
UnrealEditor-ContentBrowser-Win64-Debug.dll!UE::Core::Private::Tuple::TTupleBase<TIntegerSequence<unsigned int>>::ApplyAfter<void (__cdecl SContentBrowser::*const &)(TArrayView<FContentBrowserItem const ,int>,enum EAssetTypeActivationMethod::Type),SContentBrowser * &,TArrayView<FContentBrowserItem const ,int> &,enum EAssetTypeActivationMethod::Type &>(void(SContentBrowser::*)(TArrayView<FContentBrowserItem const ,int>, EAssetTypeActivationMethod::Type) & Func, SContentBrowser * & <Args_0>, TArrayView<FContentBrowserItem const ,int> & <Args_1>, EAssetTypeActivationMethod::Type & <Args_2>) Line 327	C++
UnrealEditor-ContentBrowser-Win64-Debug.dll!TBaseSPMethodDelegateInstance<0,SContentBrowser,1,void __cdecl(TArrayView<FContentBrowserItem const ,int>,enum EAssetTypeActivationMethod::Type),FDefaultDelegateUserPolicy>::Execute(TArrayView<FContentBrowserItem const ,int> <Params_0>, EAssetTypeActivationMethod::Type <Params_1>) Line 295	C++
UnrealEditor-ContentBrowser-Win64-Debug.dll!SAssetView::OnListMouseButtonDoubleClick(TSharedPtr<FAssetViewItem,1> AssetItem) Line 3668	C++
UnrealEditor-ContentBrowser-Win64-Debug.dll!UE::Core::Private::Tuple::TTupleBase<TIntegerSequence<unsigned int>>::ApplyAfter<void (__cdecl SAssetView::*const &)(TSharedPtr<FAssetViewItem,1>),SAssetView * &,TSharedPtr<FAssetViewItem,1> &>(void(SAssetView::*)(TSharedPtr<FAssetViewItem,1>) & Func, SAssetView * & <Args_0>, TSharedPtr<FAssetViewItem,1> & <Args_1>) Line 327	C++
UnrealEditor-ContentBrowser-Win64-Debug.dll!TBaseSPMethodDelegateInstance<0,SAssetView,1,void __cdecl(TSharedPtr<FAssetViewItem,1>),FDefaultDelegateUserPolicy>::ExecuteIfSafe(TSharedPtr<FAssetViewItem,1> <Params_0>) Line 314	C++
UnrealEditor-ContentBrowser-Win64-Debug.dll!TDelegate<void __cdecl(TSharedPtr<FAssetViewItem,1>),FDefaultDelegateUserPolicy>::ExecuteIfBound<void,0>(TSharedPtr<FAssetViewItem,1> <Params_0>) Line 639	C++
UnrealEditor-ContentBrowser-Win64-Debug.dll!SListView<TSharedPtr<FAssetViewItem,1>>::Private_OnItemDoubleClicked(TSharedPtr<FAssetViewItem,1> TheItem) Line 1115	C++
UnrealEditor-ContentBrowser-Win64-Debug.dll!STableRow<TSharedPtr<FAssetViewItem,1>>::OnMouseButtonDoubleClick(const FGeometry & InMyGeometry, const FPointerEvent & InMouseEvent) Line 422	C++
UnrealEditor-Slate-Win64-Debug.dll!FSlateApplication::RoutePointerDoubleClickEvent::__l2::<lambda>(const FArrangedWidget & TargetWidget, const FPointerEvent & Event) Line 5528	C++
UnrealEditor-Slate-Win64-Debug.dll!FEventRouter::Route<FReply,FEventRouter::FBubblePolicy,FPointerEvent,FReply <lambda>(const FArrangedWidget &, const FPointerEvent &)>(FSlateApplication * ThisApplication, FEventRouter::FBubblePolicy RoutingPolicy, FPointerEvent EventCopy, const FSlateApplication::RoutePointerDoubleClickEvent::__l2::FReply <lambda>(const FArrangedWidget &, const FPointerEvent &) & Lambda, ESlateDebuggingInputEvent DebuggingInputEvent) Line 412	C++
UnrealEditor-Slate-Win64-Debug.dll!FSlateApplication::RoutePointerDoubleClickEvent(const FWidgetPath & WidgetsUnderPointer, const FPointerEvent & PointerEvent) Line 5526	C++
UnrealEditor-Slate-Win64-Debug.dll!FSlateApplication::ProcessMouseButtonDoubleClickEvent(const TSharedPtr<FGenericWindow,1> & PlatformWindow, const FPointerEvent & InMouseEvent) Line 5511	C++
UnrealEditor-Slate-Win64-Debug.dll!FSlateApplication::OnMouseDoubleClick(const TSharedPtr<FGenericWindow,1> & PlatformWindow, const EMouseButtons::Type Button, const UE::Math::TVector2<double> CursorPos) Line 5474	C++
UnrealEditor-ApplicationCore-Win64-Debug.dll!FWindowsApplication::ProcessDeferredMessage(const FDeferredWindowsMessage & DeferredMessage) Line 2223	C++
UnrealEditor-ApplicationCore-Win64-Debug.dll!FWindowsApplication::DeferMessage(TSharedPtr<FWindowsWindow,1> & NativeWindow, HWND__ * InHWnd, unsigned int InMessage, unsigned __int64 InWParam, __int64 InLParam, int MouseX, int MouseY, unsigned int RawInputFlags) Line 2726	C++
UnrealEditor-ApplicationCore-Win64-Debug.dll!FWindowsApplication::ProcessMessage(HWND__ * hwnd, unsigned int msg, unsigned __int64 wParam, __int64 lParam) Line 1089	C++
UnrealEditor-ApplicationCore-Win64-Debug.dll!WindowsApplication_WndProc(HWND__ * hwnd, unsigned int msg, unsigned __int64 wParam, __int64 lParam) Line 919	C++
UnrealEditor-ApplicationCore-Win64-Debug.dll!FWindowsApplication::AppWndProc(HWND__ * hwnd, unsigned int msg, unsigned __int64 wParam, __int64 lParam) Line 925	C++
[External Code]	
UnrealEditor-ApplicationCore-Win64-Debug.dll!WinPumpMessages() Line 114	C++
UnrealEditor-ApplicationCore-Win64-Debug.dll!FWindowsPlatformApplicationMisc::PumpMessages(bool bFromMainLoop) Line 145	C++
UnrealEditor-Win64-Debug.exe!FEngineLoop::Tick() Line 5291	C++
UnrealEditor-Win64-Debug.exe!EngineTick() Line 67	C++
UnrealEditor-Win64-Debug.exe!GuardedMain(const wchar_t * CmdLine) Line 205	C++
UnrealEditor-Win64-Debug.exe!LaunchWindowsStartup(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow, const wchar_t * CmdLine) Line 233	C++
UnrealEditor-Win64-Debug.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * pCmdLine, int nCmdShow) Line 282	C++
[External Code]	

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Unresolved
CreatedJan 27, 2023
UpdatedFeb 13, 2024