Description

When called from Python, in 5.1 the load level invocation results in a kernel panic style crash of the editor, with a message about the map leaking memory and not being able to be garbage collected properly. So, if Python is holding a reference to the duplicated level and you try to load that level, you crash the editor.

Steps to Reproduce

def duplicate_level(src_level_path, dst_level_path):
src_lvl = ue.load_asset(src_lvl_path)
asset_tools = ue.AssetToolsHelpers.get_asset_tools()
dst_package, dst_name, _ = ue.Paths.split(dst_level_path)
dst_lvl = asset_tools.duplicate_asset(dst_name, dst_package, src_lvl)

  1. dst_lvl = None
    ue.EditorLevelLibrary.load_level(dst_level_path)
Callstack

[2023.02.07-19.33.16:942][304]LogWindows: Error: appError called: Fatal error: [Link Removed] [Line: 276]
Element 'World None.None - ID: 0' is still externally referenced when being destroyed! Ref-count: 2; see above for reference information (if available).

[2023.02.07-19.33.16:942][304]LogWindows: Windows GetLastError: The operation completed successfully. (0)
[2023.02.07-19.33.38:978][304]LogWindows: Error: === Critical error: ===
[2023.02.07-19.33.38:978][304]LogWindows: Error:
[2023.02.07-19.33.38:978][304]LogWindows: Error: Fatal error: [Link Removed] [Line: 276]
[2023.02.07-19.33.38:978][304]LogWindows: Error: Element 'World None.None - ID: 0' is still externally referenced when being destroyed! Ref-count: 2; see above for reference information (if available).
[2023.02.07-19.33.38:978][304]LogWindows: Error:
[2023.02.07-19.33.38:978][304]LogWindows: Error:
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ffb785c8339 UnrealEditor-Engine.dll!FTypedElementInternalData::CheckNoExternalReferencesOnDestruction() [D:\build\++UE5\Sync\Engine\Source\Runtime\TypedElementFramework\Public\Elements\Framework\TypedElementData.h:276]
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ffb785fb340 UnrealEditor-Engine.dll!UTypedElementRegistry::TRegisteredElementType<FObjectElementData,1>::ProcessDeferredElementsToRemove() [D:\build\++UE5\Sync\Engine\Source\Runtime\TypedElementFramework\Public\Elements\Framework\TypedElementRegistry.h:498]
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ffbaedd09c1 UnrealEditor-TypedElementFramework.dll!UTypedElementRegistry::ProcessDeferredElementsToDestroy() [D:\build\++UE5\Sync\Engine\Source\Runtime\TypedElementFramework\Private\Elements\Framework\TypedElementRegistry.cpp:151]
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ffbaedcf966 UnrealEditor-TypedElementFramework.dll!UTypedElementRegistry::OnEndFrame() [D:\build\++UE5\Sync\Engine\Source\Runtime\TypedElementFramework\Private\Elements\Framework\TypedElementRegistry.cpp:336]
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ffbaedca5f2 UnrealEditor-TypedElementFramework.dll!TBaseUObjectMethodDelegateInstance<0,UTypedElementRegistry,void __cdecl(void),FDefaultDelegateUserPolicy>::ExecuteIfSafe() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:618]
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ff6a31485d9 UnrealEditor-Win64-DebugGame.exe!TMulticastDelegate<void __cdecl(void),FDefaultDelegateUserPolicy>::Broadcast() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateSignatureImpl.inl:975]
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ff6a313bff7 UnrealEditor-Win64-DebugGame.exe!FEngineLoop::Tick() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:5627]
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ff6a315287d UnrealEditor-Win64-DebugGame.exe!GuardedMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Launch.cpp:202]
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ff6a315296a UnrealEditor-Win64-DebugGame.exe!GuardedMainWrapper() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:107]
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ff6a3155680 UnrealEditor-Win64-DebugGame.exe!LaunchWindowsStartup() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:244]
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ff6a31671c4 UnrealEditor-Win64-DebugGame.exe!WinMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:282]
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ff6a316a526 UnrealEditor-Win64-DebugGame.exe!__scrt_common_main_seh() [D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ffbe5b47614 KERNEL32.DLL!UnknownFunction []
[2023.02.07-19.33.38:978][304]LogWindows: Error: [Callstack] 0x00007ffbe76426a1 ntdll.dll!UnknownFunction []
[2023.02.07-19.33.38:978][304]LogWindows: Error:

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Non-Issue
ComponentUE - Editor - Workflow Systems
Affects Versions5.1
CreatedFeb 16, 2023
ResolvedSep 12, 2023
UpdatedJan 20, 2024