Engine crash when changing "gamemode override"

So im trying to change game mode in each level of a project that I am working on and ever since I have upgraded to 4.8.1 when I click on GameMode Override in world setting and a game mode is already in there whole engine will crash and a bar will pop up saying “rebuilding class heiarchy” and it will not allow me to change gamemode through override. is there another way of changing game mode from level to level or is this only way? if so how do I fix it?

Here is an image of crash and error report. also this does not happen in 4.7.6, so it may be a bug.

I am getting same crash after 4.8.1. Although my game crashes with no report to desktop.

Hi all,

Thanks for report! I was able to reproduce this in 4.8.1 as well as our internal build, and I’ve created a bug report for crash (UE-17673). I’ll post here as soon as I see an update on it and have a timeline for fix.

In meantime, it appears that if you open GameMode Blueprint once and compile/save it, editor won’t crash when making adjustments in World Settings tab. Please let us know if this is not case for you.


Additional workaround:
Select gameMode in Content Browser, and next to the “GameMode Override”, use arrow button to use that asset.

Unfortunately opening GameMode Blueprint, compiling and saving didn’t solve issue for me.

Setting default GameMode in project settings seems to have solved issue though.

I have same issue when changing default playercontroller but workarounds are not working and I can’t override project settings (I can but it would break game)
Although I was able to modify it by selecting new controller and clicking on “set selected asset…” (an arrow pointing to left at right of combobox)

I did find one way of working around it to change gamemode go to that panel and next to gamemode override dropdown menu click small YELLOW arrow to reset override to “none” once you have done that you can change overrides and not have engine crash you only have to do this first time

If you press any of them, its starts to rebuild and crashes

thank you lewa100g that worked :smiley:

Any ETA for this bug fix?

We don’t have a firm date yet, but a fix will be included in an upcoming hotfix. Shouldn’t be too much longer.

So weird… I logged in to report this very bug and saw it as first one.

Hi ,
This is a very similar issue, don’t know if it should be in a different thread or not. But I have a game mode defined in C++ and a player controller class defined in C++. When I create a new project, I can’t select my C++ game mode override and then select my player controller class because it is grayed out. But if I create a new game mode blueprint in GameMode Override area by clicking the ‘+’ symbol, default pawn class, HUD class, player controller class, and game state class are no longer grayed out, I can change them. So I have to create this new blueprint game mode, and then select my C++ player controller class, and then select my C++ game mode, and everything appears to work. When selecting my C++ game mode, four “Selected GameMode” combo boxes are grayed out again, however my player controller class still shows my C++ player controller class because that is what was selected when I selected my C++ game mode.

Let me know if I should create a new thread.


It doesn’t appear to be related. This crash simply involves clicking GameMode Override options in World Settings tab in Editor. You’re running into a completely different issue, sounds like. You can open a new post in Bug Reports, and we’ll assign someone to look into it.

I don’t believe it’s a bug, but I’m not 100% sure on that yet so I’ll get some C++ savvy people on it. Thanks!

Sorry for opening this up again, but I’m getting kind of same problem. (Using 4.16.2 source build)

Whenever I switch my gamemode override to NONE and then try to play game, editor crashes. Any solution to this?

It does not crash when I run it as a single process. But I do not want that (for dedicated server testing purposes)

Crash reporter is giving me this:

Assertion failed: PIEInstanceID != -1 [File:C:\Users\Hover\Desktop\UE4Source\Engine\Source\Runtime\Engine\Private\World.cpp] [Line: 2557] 

UE4Editor_Core!FDebug::AssertFailed() [c:\users\hover\desktop\ue4source\engine\source\runtime\core\private\misc\assertionmacros.cpp:349]
UE4Editor_Engine!UWorld::ConvertToPIEPackageName() [c:\users\hover\desktop\ue4source\engine\source\runtime\engine\private\world.cpp:2558]
UE4Editor_Engine!UWorld::RenameToPIEWorld() [c:\users\hover\desktop\ue4source\engine\source\runtime\engine\private\world.cpp:2531]
UE4Editor_Engine!UEngine::LoadMap() [c:\users\hover\desktop\ue4source\engine\source\runtime\engine\private\unrealengine.cpp:10150]
UE4Editor_Engine!UEngine::Browse() [c:\users\hover\desktop\ue4source\engine\source\runtime\engine\private\unrealengine.cpp:9563]
UE4Editor_Engine!UEngine::TickWorldTravel() [c:\users\hover\desktop\ue4source\engine\source\runtime\engine\private\unrealengine.cpp:9752]
UE4Editor_UnrealEd!UEditorEngine::Tick() [c:\users\hover\desktop\ue4source\engine\source\editor\unrealed\private\editorengine.cpp:1572]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [c:\users\hover\desktop\ue4source\engine\source\editor\unrealed\private\unrealedengine.cpp:386]
UE4Editor!FEngineLoop::Tick() [c:\users\hover\desktop\ue4source\engine\source\runtime\launch\private\launchengineloop.cpp:3119]
UE4Editor!GuardedMain() [c:\users\hover\desktop\ue4source\engine\source\runtime\launch\private\launch.cpp:166]
UE4Editor!GuardedMainWrapper() [c:\users\hover\desktop\ue4source\engine\source\runtime\launch\private\windows\launchwindows.cpp:134]
UE4Editor!WinMain() [c:\users\hover\desktop\ue4source\engine\source\runtime\launch\private\windows\launchwindows.cpp:210]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:259]