Instant crash attempting to run attach project in 4.7 P7

Instant crash running the attached project on Windows 8.1.

Repro:

  • Unzip project somewhere Open project
  • In 4.7 Preview 7 Should open to
  • Startup level, if not open that one
  • Click Play
  • BOOM!

EDIT:

Message and callstack:
Fatal error: [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.7\Engine\Source\Editor\UnrealEd\Private\Editor.cpp] [Line: 6987]
World /Game/Rooms/UEDPIE_0_StartupRoom.StartupRoom not cleaned up by garbage collection!
(Object is not currently rooted)

KERNELBASE.dll!UnknownFunction (0x00007ffb546b606c) + 0 bytes [UnknownFile:0]
UE4Editor-Core.dll!FOutputDeviceWindowsError::Serialize() (0x00007ffb385a68d4) + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\windows\windowsplatformoutputdevices.cpp:95]
UE4Editor-Core.dll!FMsg::Logf__VA() (0x00007ffb384276df) + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\misc\outputdevice.cpp:526]
UE4Editor-UnrealEd.dll!UEditorEngine::VerifyLoadMapWorldCleanup() (0x00007ffb33cf170f) + 143 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\private\editor.cpp:6987]
UE4Editor-Engine.dll!UEngine::LoadMap() (0x00007ffb2e54f5da) + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\unrealengine.cpp:8733]
UE4Editor-Engine.dll!UEngine::Browse() (0x00007ffb2e51bdc2) + 40 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\unrealengine.cpp:8144]
UE4Editor-Engine.dll!UEngine::TickWorldTravel() (0x00007ffb2e5672fd) + 63 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\unrealengine.cpp:8311]
UE4Editor-UnrealEd.dll!UEditorEngine::Tick() (0x00007ffb33cedcd5) + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\private\editor.cpp:1267]
UE4Editor-UnrealEd.dll!UUnrealEdEngine::Tick() (0x00007ffb341a7456) + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\private\unrealedengine.cpp:347]
UE4Editor.exe!FEngineLoop::Tick() (0x00007ff7ab1f0263) + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launchengineloop.cpp:2257]
UE4Editor.exe!GuardedMain() (0x00007ff7ab1e267c) + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor.exe!GuardedMainWrapper() (0x00007ff7ab1e26ea) + 5 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor.exe!WinMain() (0x00007ff7ab1f2219) + 17 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:202]
UE4Editor.exe!__tmainCRTStartup() (0x00007ff7ab1f3159) + 21 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]
KERNEL32.DLL!UnknownFunction (0x00007ffb564216ad) + 0 bytes [UnknownFile:0]
ntdll.dll!UnknownFunction (0x00007ffb571deb64) + 0 bytes [UnknownFile:0]
ntdll.dll!UnknownFunction (0x00007ffb571deb64) + 0 byte

Tommy.

Hey TommyBear,

We were able to repro the crash 100% with your project. I’ve reported this crash internally thanks to your repro. Thanks!

Regards,

Jonathan

The issue here is that your BP_Payload blueprint sets two actor references to variables on your game instance. Because you are opening an new level, the engine attempts to unload the current level but cannot clean it up successfully because your game instance is now referencing two actors in the level being unloaded. In order to call OpenLevel you must clear any references to existing actors first. Normally this is automatically done for you but we don’t currently clear references on the game instance. If you want to keep those actors around you could turn your level(s) into streaming levels and call LoadStreamLevel instead. This will not remove your existing level. An example of how to set that up is here: A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums.