Compiler seems to be crashing with a null pointer (C5 error). Here’s the stack.
MachineId
EpicAccountId:
Access violation - code c0000005 (first/second chance not available)
UE4Editor_CoreUObject!UObjectBaseUtility::GetOutermost() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectbaseutility.cpp:121]
UE4Editor_Engine!FArchiveReplaceOrClearExternalReferences::operator<<() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\public\serialization\archiveuobject.h:1228]
UE4Editor_CoreUObject!UObjectProperty::SerializeItem() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\propertyobject.cpp:34]
UE4Editor_CoreUObject!UStruct::SerializeBin() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:795]
UE4Editor_CoreUObject!UScriptStruct::SerializeItem() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:2845]
UE4Editor_CoreUObject!UStructProperty::SerializeItem() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\propertystruct.cpp:113]
UE4Editor_CoreUObject!UArrayProperty::SerializeItem() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\propertyarray.cpp:166]
UE4Editor_CoreUObject!UStruct::SerializeBin() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:795]
UE4Editor_CoreUObject!UScriptStruct::SerializeItem() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:2845]
UE4Editor_CoreUObject!UStructProperty::SerializeItem() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\propertystruct.cpp:113]
UE4Editor_CoreUObject!UArrayProperty::SerializeItem() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\propertyarray.cpp:166]
UE4Editor_CoreUObject!UStruct::SerializeBin() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:795]
UE4Editor_CoreUObject!UObject::SerializeScriptProperties() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\obj.cpp:1029]
UE4Editor_CoreUObject!UObject::Serialize() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\uobject\obj.cpp:956]
UE4Editor_CoreUObject!FArchiveReplaceObjectRefBase::SerializeObject() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\private\serialization\archiveuobject.cpp:198]
UE4Editor_Engine!FArchiveReplaceObjectRef::SerializeSearchObject() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\coreuobject\public\serialization\archiveuobject.h:1102]
UE4Editor_Engine!UEngine::CopyPropertiesForUnrelatedObjects() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\engine\private\unrealengine.cpp:11092]
UE4Editor_UnrealEd!FBlueprintCompileReinstancer::ReplaceInstancesOfClass_Inner() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\unrealed\private\kismet2\kismetreinstanceutilities.cpp:1418]
UE4Editor_UnrealEd!FBlueprintCompileReinstancer::ReplaceInstancesOfClass() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\unrealed\private\kismet2\kismetreinstanceutilities.cpp:1242]
UE4Editor_UnrealEd!FBlueprintCompileReinstancer::ReinstanceInner() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\unrealed\private\kismet2\kismetreinstanceutilities.cpp:573]
UE4Editor_UnrealEd!FBlueprintCompileReinstancer::ReinstanceObjects() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\unrealed\private\kismet2\kismetreinstanceutilities.cpp:698]
UE4Editor_UnrealEd!FKismetEditorUtilities::CompileBlueprint() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\unrealed\private\kismet2\kismet2.cpp:797]
UE4Editor_Kismet!FBlueprintEditor::Compile() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\kismet\private\blueprinteditor.cpp:3184]
UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,TTypeWrapper __cdecl(void)>::Execute() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:321]
UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,void __cdecl(void)>::ExecuteIfSafe() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:427]
UE4Editor_Slate!FUICommandList::ExecuteAction() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\commands\uicommandlist.cpp:87]
UE4Editor_Slate!SToolBarButtonBlock::OnClicked() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\multibox\stoolbarbuttonblock.cpp:300]
UE4Editor_Slate!TMemberFunctionCaller::operator()<>() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegateinstanceinterface_variadics.h:161]
UE4Editor_Slate!TTupleImpl >::ApplyAfter_ExplicitReturnType >() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\tuple.h:128]
UE4Editor_Slate!TBaseSPMethodDelegateInstance<0,SToolBarButtonBlock,0,FReply __cdecl(void)>::Execute() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:321]
UE4Editor_Slate!TBaseDelegate::Execute() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:521]
UE4Editor_Slate!SButton::OnMouseButtonUp() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\widgets\input\sbutton.cpp:275]
UE4Editor_Slate!::operator()() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4598]
UE4Editor_Slate!FEventRouter::Route >() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:215]
UE4Editor_Slate!FSlateApplication::RoutePointerUpEvent() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4587]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonUpEvent() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5041]
UE4Editor_Slate!FSlateApplication::OnMouseUp() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5021]
UE4Editor_Core!FWindowsApplication::ProcessDeferredMessage() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:1512]
UE4Editor_Core!FWindowsApplication::DeferMessage() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:1852]
UE4Editor_Core!FWindowsApplication::ProcessMessage() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:742]
UE4Editor_Core!FWindowsApplication::AppWndProc() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:664]
user32
user32
UE4Editor_Core!FWindowsPlatformMisc::PumpMessages() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsplatformmisc.cpp:903]
UE4Editor!FEngineLoop::Tick() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:2728]
UE4Editor!GuardedMain() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\launch.cpp:148]
UE4Editor!GuardedMainWrapper() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\build++ue4+release-4.12+compile\sync\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
Although it may be outside of the compiler, as we can see the serialization call in the stack. The blueprint has compiled to some point prior because, when opening it, the blueprint editor is showing that it is “good to go”, the wonderful green check button. But if clicking the compile button again (no changes to the blueprint), this is when it blows up.