UE 5.5.4
[2026.01.04-10.36.16:589][ 53]LogWindows: Error: appError called: Assertion failed: Result [File:D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Classes\EdGraph\EdGraphNode.h] [Line: 576]
This problem appeared when I made some changes to the blueprint /Game/Blueprints/MainCharacter/BP_CharacterBase , saved it, then compiled it, and the engine crashed. Since then, opening this blueprint or other indirectly related ones causes the engine to crash.
Project_F.log (200.5 KB)
Hi,
Locate this file in file explorer, make a backup of it outside project directories, delete it and see if that helps.
/Game/Blueprints/MainCharacter/BP_CustomCharacter.BP_CustomCharacter_C
‘/Game/Blueprints/MainCharacter/BP_CustomCharacter.BP_CustomCharacter_C’.
Make sure ‘/Game/Blueprints/MainCharacter/BP_CustomCharacter.BP_CustomCharacter_C’ has been compiled for Get IsControlledByPlayerCharacter01
[2026.01.04-10.36.15:616][ 53]LogBlueprint: Warning: [AssetLog] D:\Project__E\00\PROJECT_F\Project_F 5.5\Content\Blueprints\MainCharacter\ABP_CustomCharacter.uasset: [Compiler] Could not find a variable named “IsDead_” in ‘/Game/Blueprints/MainCharacter/BP_CustomCharacter.BP_CustomCharacter_C’.
Make sure ‘/Game/Blueprints/MainCharacter/BP_CustomCharacter.BP_CustomCharacter_C’ has been compiled for Get IsDead_
It could be ABP_CustomCharacter.uasset: too.
I’m not sure if you can recover from this, unless you have backups. You might need to re-create this class from start.
Project_F.log (242.2 KB)
Still crashes.
Also I forgot to mention this problem appeared when I made some changes to the blueprint /Game/Blueprints/MainCharacter/BP_CharacterBase , saved it, then compiled it, and the engine crashed. Since then, opening this blueprint or other indirectly related ones causes the engine to crash.
That’s probably where the problem is. If there is a problem is parent class, it probably breaks child classes.
Try to compile first, then save, so your last save is always a working (compiled) code. There is an option to auto save on compile, you can even pick to only save on successful compile, it’s an option you can enable, it’s right next to compile button if memory serves.
LOL. I restored from a backup and was able to reproduce the crash. So if you create a local variable in the function and name it “Controller“ it will actually create this not making any error. But once you compile it will crash the engine.
Well done for finding out what is the cause. It could be a naming conflict or a bug.
Does it let you create a regular variable with the same name?
Regular variable is fine - engine does not let it be named “Controller”.
Yeah I came across this before now that I think about it, but it was a while back. Either this name is reserved or used by something else inside this blueprint but it might not be visible (not exposed to blueprints)
I take it any other variable name that is not Controller/Character/Actor does work just fine? 