PIE ask to recompile unknown BP

When I deactivate “Auto Recompile Blueprints” in Editor Preferences → Level Editor → Play, I’ll always get ask if I like to recompile following BP: “PROTO_BP_Blueprint_0”.

Is this a bug or some kind of hidden feature or advice?

Hi ,

Which version of editor are you currently using? Does this occur on a clean project with no additional content?

Sorry , last compiled version 4.6. I just created and opened a top down template. Unchecked option. Press Play, no recompile. Made a change in player controller BP. Press Play. Recompile of Player Controller BP and strange one PROTO_BP_Blueprint_0 showed up.

I guess its popping up all time in my projects, cause there is still a recursive compiling issue between my player controller BP and my pawn BP (I compile one of them and other will always act a little jealously and ask for recompile also.

Hi ,

With that blueprint, when you compile it are you getting any compilation errors? There is a known issue currently that, when updating to 4.6 from another engine version. Check to make sure that your variables are referencing properly, if they are not, you can work around this by simply replacing variables in event graph with new copies of same variables. For instance, if you have a float variable (NewVar), and Get NewVar node in eventgraph says “Error” around it, delete that reference and create a new Get NewVar node and it should compile correctly.

Hi , I actually did create a new blank project from Top Down Template to test issue outside my own projects (reported same issue exists there, as you can read in my last post. My bad English, sorry, still learning).

Only one of my own project gives me in one BP a compiler warning: "No SignatureFunction in MulticastDelegateProperty ‘%s’ ", with no more info or link to any node - this warning exists since migration from version 4.2 to 4.3 and I actually hope since then that any update in future will finally come up with a proper message, so I can track it down. I know of 2 other guys reported this strange compiler message also, but both deleted and totally rebuild their BPs to fix it. I would not like go that way, would rather spend my holiday with my mother-in-law, +25 function, countless nodes, not-that-simple logic, you know.

Btw, would be nice if you could provide any hint on what a “SignatureFunction” , “MulticastDelegateProperty” or “‘%s’” actually could point to. Maybe I can narrow it down on my own.

, one more thing coming up right now (related to original issue) or I haven’t noticed it before. After changing one BP (MyControler in TopDown Template) and PIE, it shows another BP to compile: Tutorial_BP_MacroLib which is actually an empty BP (located under: Engine → Tutorial → BlueprintTutorials → TutorialAssets).

Hi ,

Can you show me a copy of blueprint that error is appearing in? I might be able to reproduce what is occurring if I can see flow of logic. Thank you.

Hi ,

We have not heard from you in quite some time. I am marking this thread as answered for tracking purposes. If you are still experiencing this error, please comment with requested information. Thank you.


We have just hit exactly same problem. We hit it while moving from 4.6 to 4.7 however.

We also run with auto compile off (lots of BP - compiles take too long else), and if we compile Playercontroller BP, and try to play PIE, we get a asked to compile two Proto blueprints (Proto_BP_Blueprint_0 and Proto_BP_AnimBlueprint_0). Failure to compile these leads to a massive list of errors while playing and a severely broken game.
Compiling them leads to game working as intended.

This did not occur to us in 4.6 using pretty much exact same PC BP.

We have no Blueprint errors in Playercontroller or any other main Blueprint classes.

Our PC BP is massive in size so it is difficult to take a picture of it. project due to its size is also difficult to share, but I can get you entire thing if you want.

You mentioned there is a known bug about variables. We have no broken variables as far as we can see, but we did take public flag away on some variables even though they are referenced in some other BP. This appears to run fine, but you never know if that is why it now does this?

Below are some of errors that occur if not compiling Proto:

PIE:Error: Error Attempt to assign variable through None from node Set RainSoundCanBeTriggered in blueprint SolusPlayer
LogScript:Warning: Cannot access ‘SolusPlayerController_C_5’. It is pending kill. Property: ‘CallFunc_GetSolusPC_ReturnValue’
SolusPlayer_C /Game/Levels/Test/UEDPIE_0_Assettest4.Assettest4:PersistentLevel.SolusPlayer_C_1
Function /Game/Blueprints/Game/SolusPlayer.SolusPlayer_C:ExecuteUbergraph_SolusPlayer:1BF5
PIE:Error: Error Cannot access ‘SolusPlayerController_C_5’. It is pending kill. Property: ‘CallFunc_GetSolusPC_ReturnValue’ from node Set RainSoundCanBeTriggered in blueprint SolusPlayer
LogScript:Warning: Attempt to assign variable through None
SolusPlayer_C /Game/Levels/Test/UEDPIE_0_Assettest4.Assettest4:PersistentLevel.SolusPlayer_C_1
Function /Game/Blueprints/Game/SolusPlayer.SolusPlayer_C:ExecuteUbergraph_SolusPlayer:1C0B
PIE:Error: Error Cannot access ‘SolusPlayerController_C_5’. It is pending kill. Property: ‘CallFunc_GetSolusPC_ReturnValue’ from node AddToViewport in blueprint SolusPlayerController
LogScript:Warning: Cannot access ‘SolusPlayerController_C_5’. It is pending kill. Property: ‘CallFunc_GetSolusPC_ReturnValue’
SolusPlayerController_C /Game/Levels/Test/UEDPIE_0_Assettest4.Assettest4:PersistentLevel.SolusPlayerController_C_22
Function /Game/Blueprints/Game/SolusPlayerController.SolusPlayerController_C:ExecuteUbergraph_SolusPlayerController:DA72
PIE:Error: Error Cannot access ‘SolusPlayerController_C_5’. It is pending kill. Property: ‘CallFunc_GetSolusPC_ReturnValue2’ from node Set CircleLoadInstance in blueprint SolusHUD
LogScript:Warning: Cannot access ‘SolusPlayerController_C_5’. It is pending kill. Property: ‘CallFunc_GetSolusPC_ReturnValue’
SolusHUD_C /Game/Levels/Test/UEDPIE_0_Assettest4.Assettest4:PersistentLevel.SolusHUD_C_1
Function /Game/Blueprints/Game/SolusHUD.SolusHUD_C:ExecuteUbergraph_SolusHUD:076B

If you return those variables to public does error stop?

Hi all,

I was able to reproduce this in 4.7.3 and in our main internal build. It looks like attempting PIE at any point while Auto Recompile Blueprints is disabled generates this error message. My guess is that errors you get when not compiling are from other Blueprints, and it’s unrelated to PROTO BP compile bug. I’ve entered a bug report for issue (UE-12038), and I mentioned that you received several errors when choosing not to compile these. I’ll let you know as soon as I see an update on issue. Thanks for your report!