[MAJOR BUG] Blueprint Graph - Transient Error

I’ve encountered a major issue in every project and blueprint I try to create. When I go to save it some time later, I go to find out that it somehow changed one of my class names to have the “REINST_” prefix. This breaks everything. It won’t let me play in the editor or anything. When I try to save the blueprint that’s having the problem, I get the following error:

[]
Can’t save …/…/…/…/…/…/Unreal Projects/QuestSystem/Content/QuestSystem/UMG/GameHUD.uasset: Graph is linked to private object(s) in an external package.
External Object(s):
/Engine/Transient
Try to find the chain of references to that object (may take some time)?
[/]

This error forbids me to save and compile. This is the third project that’s been corrupted with this error, so PLEASE, Epic, please fix this!

I’m using engine version 4.6.1.

In my current project, the error is coming from my main UMG HUD widget blueprint. Here is the Graph Code inside of it:


Begin Object Class=K2Node_CustomEvent Name="K2Node_CustomEvent_131"
   Begin Object Class=EdGraphPin Name="EdGraphPin_5519"
   End Object
   Begin Object Class=EdGraphPin Name="EdGraphPin_5520"
   End Object
   Begin Object Class=EdGraphPin Name="EdGraphPin_5521"
   End Object
   Begin Object Name="EdGraphPin_5519"
      PinName="OutputDelegate"
      Direction=EGPD_Output
      PinType=(PinCategory="delegate",PinSubCategoryObject=Function'/Game/UMG/GameHUD.SKEL_GameHUD_C:OpenQuestWindow')
   End Object
   Begin Object Name="EdGraphPin_5520"
      PinName="then"
      Direction=EGPD_Output
      PinType=(PinCategory="exec")
      LinkedTo(0)=EdGraphPin'"K2Node_VariableSet_389.EdGraphPin_5569"'
   End Object
   Begin Object Name="EdGraphPin_5521"
      PinName="NPC"
      Direction=EGPD_Output
      PinType=(PinCategory="object",PinSubCategoryObject=BlueprintGeneratedClass'/Game/QuestSystem/Blueprints/BP_NPC_Base.BP_NPC_Base_C')
      LinkedTo(0)=EdGraphPin'"K2Node_VariableSet_414.EdGraphPin_7231"'
   End Object
   CustomFunctionName="OpenQuestWindow"
   Pins(0)=EdGraphPin'EdGraphPin_5519'
   Pins(1)=EdGraphPin'EdGraphPin_5520'
   Pins(2)=EdGraphPin'EdGraphPin_5521'
   NodePosX=208
   NodePosY=256
   NodeGuid=F2C7D4834786FF2971D3FAB13FDDBA9A
   CustomProperties UserDefinedPin Name=NPC IsArray=0 IsReference=0 Category=object SubCategoryObject=/Game/QuestSystem/Blueprints/BP_NPC_Base.BP_NPC_Base_C 
End Object
Begin Object Class=K2Node_VariableSet Name="K2Node_VariableSet_389"
   Begin Object Class=EdGraphPin Name="EdGraphPin_5569"
   End Object
   Begin Object Class=EdGraphPin Name="EdGraphPin_5570"
   End Object
   Begin Object Class=EdGraphPin Name="EdGraphPin_5571"
   End Object
   Begin Object Class=EdGraphPin Name="EdGraphPin_5572"
   End Object
   Begin Object Name="EdGraphPin_5569"
      PinName="execute"
      PinType=(PinCategory="exec")
      LinkedTo(0)=EdGraphPin'"K2Node_CustomEvent_131.EdGraphPin_5520"'
   End Object
   Begin Object Name="EdGraphPin_5570"
      PinName="then"
      Direction=EGPD_Output
      PinType=(PinCategory="exec")
      LinkedTo(0)=EdGraphPin'"K2Node_VariableSet_414.EdGraphPin_7229"'
   End Object
   Begin Object Name="EdGraphPin_5571"
      PinName="QuestWindowVisibility"
      PinType=(PinCategory="byte",PinSubCategoryObject=Enum'/Script/UMG.ESlateVisibility')
      DefaultValue="Visible"
   End Object
   Begin Object Name="EdGraphPin_5572"
      PinName="self"
      PinFriendlyName="Target"
      PinType=(PinCategory="object",PinSubCategoryObject=WidgetBlueprintGeneratedClass'/Game/UMG/GameHUD.GameHUD_C')
      bHidden=True
   End Object
   VariableReference=(MemberName="QuestWindowVisibility",bSelfContext=True)
   Pins(0)=EdGraphPin'EdGraphPin_5569'
   Pins(1)=EdGraphPin'EdGraphPin_5570'
   Pins(2)=EdGraphPin'EdGraphPin_5571'
   Pins(3)=EdGraphPin'EdGraphPin_5572'
   NodePosX=448
   NodePosY=224
   ErrorType=1
   ErrorMsg="Error This blueprint (self) is not a GameHUD_C, therefore \' Target \' must have a connection"
   NodeGuid=40F8D2AB494413C926D45AB5BC3F6321
End Object
Begin Object Class=K2Node_VariableSet Name="K2Node_VariableSet_414"
   Begin Object Class=EdGraphPin Name="EdGraphPin_7229"
   End Object
   Begin Object Class=EdGraphPin Name="EdGraphPin_7230"
   End Object
   Begin Object Class=EdGraphPin Name="EdGraphPin_7231"
   End Object
   Begin Object Class=EdGraphPin Name="EdGraphPin_7232"
   End Object
   Begin Object Name="EdGraphPin_7229"
      PinName="execute"
      PinType=(PinCategory="exec")
      LinkedTo(0)=EdGraphPin'"K2Node_VariableSet_389.EdGraphPin_5570"'
   End Object
   Begin Object Name="EdGraphPin_7230"
      PinName="then"
      Direction=EGPD_Output
      PinType=(PinCategory="exec")
      LinkedTo(0)=EdGraphPin'"K2Node_CallFunction_2789.EdGraphPin_7241"'
   End Object
   Begin Object Name="EdGraphPin_7231"
      PinName="NPC"
      PinType=(PinCategory="object",PinSubCategoryObject=BlueprintGeneratedClass'/Game/QuestSystem/Blueprints/BP_NPC_Base.BP_NPC_Base_C')
      LinkedTo(0)=EdGraphPin'"K2Node_CustomEvent_131.EdGraphPin_5521"'
   End Object
   Begin Object Name="EdGraphPin_7232"
      PinName="self"
      PinFriendlyName="Target"
      PinType=(PinCategory="object",PinSubCategoryObject=WidgetBlueprintGeneratedClass'/Game/QuestSystem/UMG/QuestWindowWidget.QuestWindowWidget_C')
   End Object
   VariableReference=(MemberParentClass=WidgetBlueprintGeneratedClass'/Game/QuestSystem/UMG/QuestWindowWidget.QuestWindowWidget_C',MemberName="NPC",MemberGuid=C604C9054DC282FC8ECCE6B7501E7528)
   SelfContextInfo=NotSelfContext
   Pins(0)=EdGraphPin'EdGraphPin_7229'
   Pins(1)=EdGraphPin'EdGraphPin_7230'
   Pins(2)=EdGraphPin'EdGraphPin_7231'
   Pins(3)=EdGraphPin'EdGraphPin_7232'
   NodePosX=896
   NodePosY=304
   bHasCompilerMessage=True
   ErrorType=1
   ErrorMsg="Error This blueprint (self) is not a QuestWindowWidget_C, therefore \' Target \' must have a connection
Error Variable node  Set NPC  uses an invalid target.  It may depend on a node that is not connected to the execution chain, and got purged.
Error This blueprint (self) is not a QuestWindowWidget_C, therefore \' Target \' must have a connection"
   NodeGuid=0606BB6F45E8066B0A3B30B162100349
End Object
Begin Object Class=K2Node_CallFunction Name="K2Node_CallFunction_2789"
   Begin Object Class=EdGraphPin Name="EdGraphPin_7241"
   End Object
   Begin Object Class=EdGraphPin Name="EdGraphPin_7242"
   End Object
   Begin Object Class=EdGraphPin Name="EdGraphPin_7243"
   End Object
   Begin Object Name="EdGraphPin_7241"
      PinName="execute"
      PinType=(PinCategory="exec")
      LinkedTo(0)=EdGraphPin'"K2Node_VariableSet_414.EdGraphPin_7230"'
   End Object
   Begin Object Name="EdGraphPin_7242"
      PinName="then"
      Direction=EGPD_Output
      PinType=(PinCategory="exec")
   End Object
   Begin Object Name="EdGraphPin_7243"
      PinName="self"
      PinFriendlyName="Target"
      PinToolTip="Target
Quest Window Widget Reference"
      PinType=(PinCategory="object",PinSubCategoryObject=WidgetBlueprintGeneratedClass'/Game/QuestSystem/UMG/QuestWindowWidget.QuestWindowWidget_C')
   End Object
   FunctionReference=(MemberParentClass=WidgetBlueprintGeneratedClass'/Game/QuestSystem/UMG/QuestWindowWidget.QuestWindowWidget_C',MemberName="RefreshInterface",MemberGuid=7A4A278248A3EAD601AA56BC938ABF80)
   Pins(0)=EdGraphPin'EdGraphPin_7241'
   Pins(1)=EdGraphPin'EdGraphPin_7242'
   Pins(2)=EdGraphPin'EdGraphPin_7243'
   NodePosX=1120
   NodePosY=320
   bHasCompilerMessage=True
   ErrorType=1
   ErrorMsg="Error This blueprint (self) is not a QuestWindowWidget_C, therefore \' Target \' must have a connection
Error This blueprint (self) is not a QuestWindowWidget_C, therefore \' Target \' must have a connection"
   NodeGuid=43BF69F045DFF41126EB25B6BC0A59B2
End Object


Hi Devfo Studios,

Please post this to the answerhub at http://answers.unrealengine.com in the bug reports section so we can better assist you. In the bug report on the answerhub, please list what steps you had taken that lead up to this error occurring. Thank you.

I had the same problem ( https://answers.unrealengine.com/questions/148627/461-umg-widget-inside-widget-bug.html )

This may be happening because you made some very bad mistake in your code and engine does not understand, what to do first and how this will work.

For example…
Actor blueprint, that has some function from FuncLibrary. But other function in the same library references to that blueprint. So that is the question, what do u need to compile first?

I had this problem, when was about to make UMG widget, that had another widget as a child. But In this child widget I wanted to reference my main widget. And that gave me alot of troubles…

I’m not very good in technical things, but I think you must organize your code differently, so the engine understand how this will work consistently.

I’ve also been experiencing this issue; specifically with UMG widgets.

Its probably a circular reference error. You need to make sure any widgets you have inside of another widget do not directly reference the parent widget.

https://www…com/watch?v=IahTICpWifw

Thank you so much! That video is exactly what I needed! It seems that the problem is with UMG and is avoidable by using Blueprint Interfaces!