Editor Crash on Startup (Asseration Failed:UOBJECT)

Hello guys,
everytime i am starting my project the editor crashs. To reproduce the issue you can use the GenericShooter Template from M. Allar. - that project is suffering from the same bug. This appears to be an issue based on the GetDefaultsNode breaking in 4.12.

JCInventory Marketplace Asset is also affected by this bug.

Hi ,

We are looking into this on our end. While I am able to reproduce the error in the Generic Shooter project, I have not been able to do so in a clean, blank project with no additional content. Have you been able to do so in a new project or is this limited to marketplace assets?

We are also having this issue with RTS Building Template in 4.12

Hi ,
this seems to be related togithub.com/EpicGames/UnrealEngine/commit/fceb5e3b370956b30b3519f97de3c60f75147e49

Originally under 4.12.0 the nodes kept breaking. I was able to update the project originially from 4.11 but after 4.12.3 the project can no longer be started.

Hey there,

I made a question with info here is the link:

The problem starts after converting a working 4.11 project to 4.12 after this the engine crashes on lunch, above says that it looks like an issue with get class default node breaking which this project does use.

Hi ,

  • Please let me know what steps you are taking that lead to this crash.
  • Can you post your crash logs and callstack so I can take a look?
  • What steps can I take to reproduce this on my end?

We are looking into what may be occurring as this seems limited to marketplace assets. If anyone has steps I can take to reproduce this in a new project it would be extremely helpful.

I’ve entered a bug report, UE-32356, to be assessed by the development staff.

I tried migrating broken BPs as well. Gonna make 2 assumptions here, it happens on UMG BPs and those BPs utilize GetClassDefaults(). Could you confirm your affected BPs are UMG as well and contain this node ?

Just to update. I posted the original bug report about the “GetClassDefaults” disconnecting after converting.

I just had time to try updating my project again and I suffer from this bug here too.

So you can probably add my 4.11 project, which I already send you, to the list. Upgrading it to 4.12.3 makes it crash when I hit play or try to open a BP that uses the GetClassDefaults node.


EDIT: Ok, it crashs when trying to open any of the Blueprints or press Play.

Here is the error, just so you have some more stuff to work with:

Assertion failed: !HasAnyFlags(RF_NeedLoad|RF_NeedPostLoad) [File:D:\Build++UE4+Release-4.12+Compile\Sync\Engine\Source\Runtime\CoreUObject\Private\UObject\UObjectLinker.cpp] [Line: 102]
Detaching from existing linker for …/…/…/…/…/…/UnrealEngineProjekte/KillStreak 4.12/Content/KillStreak/Blueprints/BlueprintsForKillStreakSystem/Widgets/KSR_Displayer.uasset while object ObjectProperty /Engine/Transient.TRASHCLASS_KSR_Displayer_21:ObjectProperty_63 needs loaded

EDIT: Even deleting them in the Editor crashs. So accessing them at all makes the Editor Crash. :x


I managed to fix it. I moved my broken Asset (in the Crash Error it’s “KSR_Displayer”) as well as all other Widgets (couldn’t remember which of them had a “GetClassDefaults” node and which not) to the top most folder “Content” in my Windows Explorer (not in the editor):


Now I reopened the Project. It doesn’t crash anymore, but all references of these Widgets were set to “Object”. So I needed to set the Reference Variables back to their original Type, as well as re-select the “Class To Spawn” for the “Create Widget” nodes. After that, I needed to connect the Reference variable wires back to all their “AddToViewport” stuff and it’s working again.

You can move the files back to their original location INSIDE of the Editor, once you fixed all reference errors. It won’t break again.

While this might not be a solution for really big projects, it can be used to fix the error for now. Cheers!

I can’t speak for Generic Shooter, since I don’t own it and it might be way bigger than my project. Make sure to move all files that are reported in the Crash Log. I think, by moving them, the Engine things you removed them and recreated them. So it kills all flags and all references (that’s why I needed to redo them).

(: Nice, haven’t had time to update my own project, otherwise I could’ve helped earlier. Glad it works! Cheers!

Awesome! Thanks for posting a work around here…
Edit: Doesn’t work for GenericShooter. Gonna try in my own project now.

There was a file missing that i didn’t move. Able to open the project now again. Again, thanks for this one, been waiting for a fix for 2 weeks now.

I reproduced this with a blank project.

create interfaceBP,function,
duplicate the BP,change its function’s name,
introduce the two interfaces into a ActorBP.
When this actor loaded by engine ,the crash caused.