Hey, I’m running into an issue while working with state trees that I can’t seem to solve. the issue happens whenever I load in / exit a scene. This only happens specifically if there is a state tree that has any node with a blueprint made condition, c++ made conditions work fine on the other hand. this issue also only occurs in a packaged build and not in the editor or standalone.
I get the following crash report
[2025.06.02-14.29.01:448][841]LogGarbage: Warning: Disregard for GC object StateTree /Game/Game/Characters/Test/ST_Test.ST_Test referencing STC_Test_C /Game/Game/Characters/Test/ST_Test.ST_Test:STC_Test_C_2147482083 which is not part of root set
[2025.06.02-14.29.01:450][841]LogOutputDevice: Warning:
Script Stack (0 frames) :
[2025.06.02-14.29.01:450][841]LogWindows: Error: appError called: Fatal error: [File:C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\CoreUObject\Private\UObject\GarbageCollectionVerification.cpp] [Line: 154]
Encountered 1 object(s) breaking Disregard for GC assumptions. Please check log for details.
[2025.06.02-14.29.01:451][841]LogWindows: Windows GetLastError: The operation completed successfully. (0)
[2025.06.02-14.29.02:800][841]LogWindows: Error: begin: stack for UAT
[2025.06.02-14.29.02:801][841]LogWindows: Error: === Critical error: ===
[2025.06.02-14.29.02:802][841]LogWindows: Error:
[2025.06.02-14.29.02:802][841]LogWindows: Error: Fatal error: [File:C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\CoreUObject\Private\UObject\GarbageCollectionVerification.cpp] [Line: 154]
[2025.06.02-14.29.02:803][841]LogWindows: Error: Encountered 1 object(s) breaking Disregard for GC assumptions. Please check log for details.
[2025.06.02-14.29.02:803][841]LogWindows: Error:
[2025.06.02-14.29.02:803][841]LogWindows: Error:
[2025.06.02-14.29.02:804][841]LogWindows: Error: [Callstack] 0x00007ff7060f1953 GardenWall.exe!VerifyGCAssumptions() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\CoreUObject\Private\UObject\GarbageCollectionVerification.cpp:155]
[2025.06.02-14.29.02:804][841]LogWindows: Error: [Callstack] 0x00007ff705f85fc5 GardenWall.exe!UE::GC::PreCollectGarbageImpl<1>() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\CoreUObject\Private\UObject\GarbageCollection.cpp:5465]
[2025.06.02-14.29.02:805][841]LogWindows: Error: [Callstack] 0x00007ff706004923 GardenWall.exe!UE::GC::FReachabilityAnalysisState::PerformReachabilityAnalysisAndConditionallyPurgeGarbage() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\CoreUObject\Private\UObject\GarbageCollection.cpp:5664]
[2025.06.02-14.29.02:805][841]LogWindows: Error: [Callstack] 0x00007ff705fb2f8b GardenWall.exe!CollectGarbage() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\CoreUObject\Private\UObject\GarbageCollection.cpp:6007]
[2025.06.02-14.29.02:805][841]LogWindows: Error: [Callstack] 0x00007ff70c7c4dbd GardenWall.exe!UEngine::TrimMemory() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\Engine\Private\UnrealEngine.cpp:15593]
[2025.06.02-14.29.02:806][841]LogWindows: Error: [Callstack] 0x00007ff70c77f395 GardenWall.exe!UEngine::LoadMap() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\Engine\Private\UnrealEngine.cpp:15194]
[2025.06.02-14.29.02:806][841]LogWindows: Error: [Callstack] 0x00007ff70c702785 GardenWall.exe!UEngine::Browse() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\Engine\Private\UnrealEngine.cpp:14670]
[2025.06.02-14.29.02:807][841]LogWindows: Error: [Callstack] 0x00007ff70c7bdb5f GardenWall.exe!UEngine::TickWorldTravel() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\Engine\Private\UnrealEngine.cpp:14868]
[2025.06.02-14.29.02:807][841]LogWindows: Error: [Callstack] 0x00007ff70b918816 GardenWall.exe!UGameEngine::Tick() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\Engine\Private\GameEngine.cpp:1775]
[2025.06.02-14.29.02:808][841]LogWindows: Error: [Callstack] 0x00007ff70cf98b13 GardenWall.exe!FEngineLoop::Tick() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:5921]
[2025.06.02-14.29.02:808][841]LogWindows: Error: [Callstack] 0x00007ff70cfb0f8c GardenWall.exe!GuardedMain() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\Launch\Private\Launch.cpp:180]
[2025.06.02-14.29.02:808][841]LogWindows: Error: [Callstack] 0x00007ff70cfb105a GardenWall.exe!GuardedMainWrapper() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:118]
[2025.06.02-14.29.02:809][841]LogWindows: Error: [Callstack] 0x00007ff70cfb3c66 GardenWall.exe!LaunchWindowsStartup() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:258]
[2025.06.02-14.29.02:809][841]LogWindows: Error: [Callstack] 0x00007ff70cfc4114 GardenWall.exe!WinMain() [C:\Perforce\Verdant\UnrealEngine\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:299]
[2025.06.02-14.29.02:810][841]LogWindows: Error: [Callstack] 0x00007ff7112e361a GardenWall.exe!__scrt_common_main_seh() [D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
[2025.06.02-14.29.02:810][841]LogWindows: Error: [Callstack] 0x00007ffdecb97374 KERNEL32.DLL!UnknownFunction []
[2025.06.02-14.29.02:810][841]LogWindows: Error:
[2025.06.02-14.29.02:811][841]LogWindows: Error: end: stack for UAT
[2025.06.02-14.29.02:830][841]LogExit: Executing StaticShutdownAfterError
[2025.06.02-14.29.02:831][841]LogWindows: FPlatformMisc::RequestExit(1, LaunchWindowsStartup.ExceptionHandler)
[2025.06.02-14.29.02:831][841]LogWindows: FPlatformMisc::RequestExitWithStatus(1, 3, LaunchWindowsStartup.ExceptionHandler)
[2025.06.02-14.29.02:832][841]LogCore: Engine exit requested (reason: Win RequestExit)
as you can see it somehow related to the garbage collection system. Adding the following code to UStateTreeConditionBlueprintBase inside PostInitProperties() seems to prevent it from crashing but its obvious not a good thing to do.
if (!HasAnyFlags(RF_ClassDefaultObject))
{
this->AddToRoot(); // TEMPORARY: Prevent GC
}
I am a bit at a loss right now on how to solve this, so any help or insight is highly appreciated.