"Found unexpected ChildActorTemplate" crash after Load Stream Level

Load Stream Level crashes the game in PIE using version 4.18.3. For some reason it doesn’t log the crash call stack so I had to copy call stack from Visual Studio:

[Inline Frame] UE4Editor-Engine.dll!FWindowsPlatformMisc::DebugBreak() Line 56	
[Inline Frame] UE4Editor-Engine.dll!FWindowsPlatformMisc::DebugBreakAndPromptForRemoteReturningFalse(bool) Line 80	
UE4Editor-Engine.dll!UChildActorComponent::Serialize(FArchive & Ar) Line 95	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
UE4Editor-CoreUObject.dll!UArrayProperty::SerializeItem(FArchive & Ar, void * Value, const void * Defaults) Line 210	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!UActorComponent::Serialize(FArchive & Ar) Line 1792	
UE4Editor-Engine.dll!USceneComponent::Serialize(FArchive & Ar) Line 2210	
UE4Editor-Engine.dll!UChildActorComponent::Serialize(FArchive & Ar) Line 59	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
UE4Editor-CoreUObject.dll!UArrayProperty::SerializeItem(FArchive & Ar, void * Value, const void * Defaults) Line 210	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!UActorComponent::Serialize(FArchive & Ar) Line 1792	
UE4Editor-Engine.dll!USceneComponent::Serialize(FArchive & Ar) Line 2210	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!UActorComponent::Serialize(FArchive & Ar) Line 1792	
UE4Editor-Engine.dll!USceneComponent::Serialize(FArchive & Ar) Line 2210	
UE4Editor-Engine.dll!UChildActorComponent::Serialize(FArchive & Ar) Line 59	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!AActor::Serialize(FArchive & Ar) Line 559	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UScriptStruct::SerializeItem(FArchive & Ar, void * Value, const void * Defaults) Line 2034	
UE4Editor-CoreUObject.dll!UStructProperty::SerializeItem(FArchive & Ar, void * Value, const void * Defaults) Line 116	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!AActor::Serialize(FArchive & Ar) Line 559	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!UActorComponent::Serialize(FArchive & Ar) Line 1792	
UE4Editor-Engine.dll!USceneComponent::Serialize(FArchive & Ar) Line 2210	
UE4Editor-Engine.dll!UChildActorComponent::Serialize(FArchive & Ar) Line 59	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!UActorComponent::Serialize(FArchive & Ar) Line 1792	
UE4Editor-Engine.dll!USceneComponent::Serialize(FArchive & Ar) Line 2210	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!UActorComponent::Serialize(FArchive & Ar) Line 1792	
UE4Editor-Engine.dll!USceneComponent::Serialize(FArchive & Ar) Line 2210	
UE4Editor-Engine.dll!UPrimitiveComponent::Serialize(FArchive & Ar) Line 762	
UE4Editor-Engine.dll!UStaticMeshComponent::Serialize(FArchive & Ar) Line 296	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!AActor::Serialize(FArchive & Ar) Line 559	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!UActorChannel::Serialize(FArchive & Ar) Line 2637	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
UE4Editor-CoreUObject.dll!UArrayProperty::SerializeItem(FArchive & Ar, void * Value, const void * Defaults) Line 210	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!UNetConnection::Serialize(FArchive & Ar) Line 356	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!AActor::Serialize(FArchive & Ar) Line 559	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!AActor::Serialize(FArchive & Ar) Line 559	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!AActor::Serialize(FArchive & Ar) Line 559	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!AActor::Serialize(FArchive & Ar) Line 559	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-Engine.dll!operator<<(FArchive &) Line 92	
UE4Editor-Engine.dll!operator<<(FArchive & Ar, TArray<AActor *,FDefaultAllocator> & A) Line 1097	
UE4Editor-Engine.dll!ULevel::Serialize(FArchive & Ar) Line 315	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-CoreUObject.dll!UProperty::SerializeBinProperty(FArchive &) Line 269	
UE4Editor-CoreUObject.dll!UStruct::SerializeBin(FArchive & Ar, void * Data) Line 837	
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties(FArchive & Ar) Line 1298	
UE4Editor-CoreUObject.dll!UObject::Serialize(FArchive & Ar) Line 1215	
UE4Editor-Engine.dll!UWorld::Serialize(FArchive & Ar) Line 361	
UE4Editor-Engine.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 2641	
[Inline Frame] UE4Editor-Engine.dll!operator<<(FArchive &) Line 734	
UE4Editor-Engine.dll!UWorld::DuplicateWorldForPIE(const FString & PackageName, UWorld * OwningWorld) Line 2717	
UE4Editor-Engine.dll!ULevelStreaming::RequestLevel(UWorld * PersistentWorld, bool bAllowLevelLoadRequests, ULevelStreaming::EReqLevelBlock BlockPolicy) Line 463	
UE4Editor-Engine.dll!UWorld::UpdateLevelStreamingInner(ULevelStreaming * StreamingLevel) Line 2839	
UE4Editor-Engine.dll!UWorld::UpdateLevelStreaming() Line 2918	
UE4Editor-Engine.dll!UGameViewportClient::Draw(FViewport * InViewport, FCanvas * SceneCanvas) Line 1229	
UE4Editor-Engine.dll!FViewport::Draw(bool bShouldPresent) Line 1213	
UE4Editor-UnrealEd.dll!UEditorEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 1862	
UE4Editor-UnrealEd.dll!UUnrealEdEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 396	
UE4Editor.exe!FEngineLoop::Tick() Line 3296	
[Inline Frame] UE4Editor.exe!EngineTick() Line 62	
UE4Editor.exe!GuardedMain(const wchar_t * CmdLine, HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, int nCmdShow) Line 166	
UE4Editor.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow) Line 199	

It has something to do with child actor components but solutions from https://answers.unrealengine.com/questions/604285/416-updated-project-crashes-skel-linkerplaceholder.html didn’t help.

If child actor components mentioned in error message are removed then it’ll work, but it’ll be too bothersome to replace all child actor components with actors.

Hello,

We’ve recently made a switch to a new bug reporting method using a more structured form. Please visit the link below for more details and report the issue using the new Bug Submission Form. Feel free to continue to use this thread for community discussion around the issue.

https://forums.unrealengine.com/unreal-engine/announcements-and-releases/1410408-unreal-engine-bug-submission-form

Thanks