# Ue4 editor crashes when recompiling code, VTable ptr **URL:** \ **Category:** Unreal Engine\ **Created:** [April 5, 2022, 5:18am UTC](https://qa.fmod.com/t/ue4-editor-crashes-when-recompiling-code-vtable-ptr/18619 "2022-04-05T05:18:30Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Tarfax](https://avatars.discourse-cdn.com/v4/letter/t/d9b06d/32.png) [@Tarfax](https://qa.fmod.com/u/Tarfax)\ **Post date:** [April 5, 2022, 5:18am UTC](https://qa.fmod.com/t/ue4-editor-crashes-when-recompiling-code-vtable-ptr/18619/1 "2022-04-05T05:18:30Z")
This wasn’t a problem before, but when I started using programmer instruments with our localization team the editor keeps crashing every time I recompile the code. It doesn’t matter what code, the same crash report shows up. Any idea why this happens? ![image](https://canada1.discourse-cdn.com/flex036/uploads/fmod/original/2X/4/4b63efea60c879815775b0e2cb8eb191385eae03.png) ---
**Author:** ![jeff\_fmod](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/jeff_fmod/32/1766_2.png) [@jeff\_fmod](https://qa.fmod.com/u/jeff_fmod)\ **Post date:** [April 8, 2022, 5:57am UTC](https://qa.fmod.com/t/ue4-editor-crashes-when-recompiling-code-vtable-ptr/18619/2 "2022-04-08T05:57:51Z")
What version of FMOD and Unreal are you using? ---
**Author:** ![Tarfax](https://avatars.discourse-cdn.com/v4/letter/t/d9b06d/32.png) [@Tarfax](https://qa.fmod.com/u/Tarfax)\ **Post date:** [April 8, 2022, 11:29am UTC](https://qa.fmod.com/t/ue4-editor-crashes-when-recompiling-code-vtable-ptr/18619/3 "2022-04-08T11:29:54Z")
Its Ue4 4.27.2 and FMOD 2.02.06 so everything is latest. For what I can tell, anything that I reference that has to do with FMOD will cause this crash when recompiling the code. Adding a FmodAudioComponent makes this crash, referencing a bank asset for load or unloading banks causes this crash, just having an event referenced as a function input causes this crash. I ended up removing every reference to Fmod in c++ and is now doing everything in blueprints instead. ---
**Author:** ![Acodeon](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/acodeon/32/4505_2.png) [@Acodeon](https://qa.fmod.com/u/Acodeon)\ **Post date:** [January 20, 2023, 7:59am UTC](https://qa.fmod.com/t/ue4-editor-crashes-when-recompiling-code-vtable-ptr/18619/4 "2023-01-20T07:59:57Z")
I’m getting the same crash, any solutions? ---
**Author:** ![jeff\_fmod](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/jeff_fmod/32/1766_2.png) [@jeff\_fmod](https://qa.fmod.com/u/jeff_fmod)\ **Post date:** [January 22, 2023, 9:50pm UTC](https://qa.fmod.com/t/ue4-editor-crashes-when-recompiling-code-vtable-ptr/18619/5 "2023-01-22T21:50:51Z")
What version of FMOD and Unreal are you using? ---
**Author:** ![Acodeon](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/acodeon/32/4505_2.png) [@Acodeon](https://qa.fmod.com/u/Acodeon)\ **Post date:** [January 23, 2023, 8:46am UTC](https://qa.fmod.com/t/ue4-editor-crashes-when-recompiling-code-vtable-ptr/18619/6 "2023-01-23T08:46:56Z")
Unreal 4.27 and FMOD plugin 2.02.07 ---
**Author:** ![jeff\_fmod](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/jeff_fmod/32/1766_2.png) [@jeff\_fmod](https://qa.fmod.com/u/jeff_fmod)\ **Post date:** [January 23, 2023, 11:31pm UTC](https://qa.fmod.com/t/ue4-editor-crashes-when-recompiling-code-vtable-ptr/18619/7 "2023-01-23T23:31:09Z")
Thank you for the additional information. The trace from the previously posted crash is indicating an issue with the sequencer- are you scripting anything related to FMOD events in the Unreal sequencer? If not, can you please share the crash you are getting, and provide a little more information on when this crash started occurring? ---
**Author:** ![osome](https://avatars.discourse-cdn.com/v4/letter/o/ee59a6/32.png) [@osome](https://qa.fmod.com/u/osome)\ **Post date:** [February 6, 2023, 9:45am UTC](https://qa.fmod.com/t/ue4-editor-crashes-when-recompiling-code-vtable-ptr/18619/8 "2023-02-06T09:45:33Z")
Hi, We have same problem here, when we put any UFModEvent\* property in any C++ class. ```auto Fatal error: [File:D:/Build/++UE4/Sync/Engine/Source/Runtime/CoreUObject/Private/UObject/Obj.cpp] [Line: 107] We are currently retrieving VTable ptr. Please use FVTableHelper constructor instead. UE4Editor_CoreUObject UE4Editor_CoreUObject UE4Editor_CoreUObject UE4Editor_CoreUObject UE4Editor_FMODStudio_0004!Z_Construct_UDelegateFunction_FMODStudio_OnEventStopped__DelegateSignature() [....\Plugins\FMODStudio\Intermediate\Build\Win64\UE4Editor\Inc\FMODStudio\FMODAudioComponent.gen.cpp:143] UE4Editor_CoreUObject UE4Editor_FMODStudio_0004!Z_Construct_UPackage__Script_FMODStudio() [....\Plugins\FMODStudio\Intermediate\Build\Win64\UE4Editor\Inc\FMODStudio\FMODStudio.init.gen.cpp:38] UE4Editor_FMODStudio_0004!StaticEnum() [....\Plugins\FMODStudio\Intermediate\Build\Win64\UE4Editor\Inc\FMODStudio\FMODEventControlSection.gen.cpp:35] UE4Editor_FMODStudio_0004!FFMODEventControlChannel::FFMODEventControlChannel() [....\Plugins\FMODStudio\Source\FMODStudio\Private\Sequencer\FMODEventControlSection.cpp:10] UE4Editor_FMODStudio_0004!InternalVTableHelperCtorCaller() [C:\Program Files\Epic Games\UE_4.27\Engine\Source\Runtime\CoreUObject\Public\UObject\Class.h:3386] UE4Editor_CoreUObject UE4Editor_CoreUObject UE4Editor_FMODStudio_0004!UFMODEventControlSection::GetPrivateStaticClass() [....\Plugins\FMODStudio\Intermediate\Build\Win64\UE4Editor\Inc\FMODStudio\FMODEventControlSection.gen.cpp:221] UE4Editor_FMODStudio_0004!TClassCompiledInDefer::Register() [C:\Program Files\Epic Games\UE_4.27\Engine\Source\Runtime\CoreUObject\Public\UObject\UObjectBase.h:301] UE4Editor_CoreUObject UE4Editor_CoreUObject UE4Editor_CoreUObject UE4Editor_Core UE4Editor_Core UE4Editor_Core UE4Editor_HotReload UE4Editor_HotReload UE4Editor_HotReload UE4Editor_Core UE4Editor UE4Editor UE4Editor UE4Editor UE4Editor UE4Editor kernel32 ntdll ``` Call stack with engine source code ```auto > [Inline Frame] UE4Editor-CoreUObject.dll!UObject::EnsureNotRetrievingVTablePtr::__l10::::()::__l6::::operator()() Line 107 C++ [Inline Frame] UE4Editor-CoreUObject.dll!UObject::EnsureNotRetrievingVTablePtr::__l10::::operator()(const FLogCategoryLogCore & LCategoryName, const wchar_t[86] &) Line 107 C++ UE4Editor-CoreUObject.dll!UObject::EnsureNotRetrievingVTablePtr() Line 107 C++ UE4Editor-CoreUObject.dll!UObject::UObject(const FObjectInitializer & ObjectInitializer) Line 2618 C++ [Inline Frame] UE4Editor-CoreUObject.dll!UField::{ctor}(const FObjectInitializer &) Line 66 C++ [Inline Frame] UE4Editor-CoreUObject.dll!UStruct::{ctor}(const FObjectInitializer &) Line 675 C++ UE4Editor-CoreUObject.dll!UFunction::UFunction(const FObjectInitializer & ObjectInitializer, UFunction * InSuperFunction, EFunctionFlags InFunctionFlags, unsigned __int64 ParamsSize) Line 5614 C++ UE4Editor-CoreUObject.dll!UDelegateFunction::UDelegateFunction(const FObjectInitializer & ObjectInitializer, UFunction * InSuperFunction, EFunctionFlags InFunctionFlags, unsigned __int64 ParamsSize) Line 6121 C++ UE4Editor-CoreUObject.dll!UE4CodeGen_Private::ConstructUFunction(UFunction * & OutFunction, const UE4CodeGen_Private::FFunctionParams & Params) Line 4499 C++ UE4Editor-FMODStudio-0001.dll!Z_Construct_UDelegateFunction_FMODStudio_OnEventStopped__DelegateSignature() Line 143 C++ UE4Editor-CoreUObject.dll!UE4CodeGen_Private::ConstructUPackage(UPackage * & OutPackage, const UE4CodeGen_Private::FPackageParams & Params) Line 4635 C++ UE4Editor-FMODStudio-0001.dll!Z_Construct_UPackage__Script_FMODStudio() Line 38 C++ [Inline Frame] UE4Editor-FMODStudio-0001.dll!EFMODEventControlKey_StaticEnum() Line 29 C++ UE4Editor-FMODStudio-0001.dll!StaticEnum() Line 35 C++ UE4Editor-FMODStudio-0001.dll!FFMODEventControlChannel::FFMODEventControlChannel() Line 10 C++ [Inline Frame] UE4Editor-FMODStudio-0001.dll!UFMODEventControlSection::{ctor}(FVTableHelper &) Line 227 C++ [Inline Frame] UE4Editor-FMODStudio-0001.dll!UFMODEventControlSection::__VTableCtorCaller(FVTableHelper &) Line 52 C++ UE4Editor-FMODStudio-0001.dll!InternalVTableHelperCtorCaller(FVTableHelper & Helper) Line 3386 C++ UE4Editor-CoreUObject.dll!UClass::HotReloadPrivateStaticClass(unsigned int InSize, EClassFlags InClassFlags, EClassCastFlags InClassCastFlags, const wchar_t * InConfigName, void(*)(const FObjectInitializer &) InClassConstructor, UObject *(*)(FVTableHelper &) InClassVTableHelperCtorCaller, void(*)(UObject *, FReferenceCollector &) InClassAddReferencedObjects, UClass * TClass_Super_StaticClass, UClass * TClass_WithinClass_StaticClass) Line 5125 C++ UE4Editor-CoreUObject.dll!GetPrivateStaticClassBody(const wchar_t * PackageName, const wchar_t * Name, UClass * & ReturnClass, void(*)() RegisterNativeFunc, unsigned int InSize, unsigned int InAlignment, EClassFlags InClassFlags, EClassCastFlags InClassCastFlags, const wchar_t * InConfigName, void(*)(const FObjectInitializer &) InClassConstructor, UObject *(*)(FVTableHelper &) InClassVTableHelperCtorCaller, void(*)(UObject *, FReferenceCollector &) InClassAddReferencedObjects, UClass *(*)() InSuperClassFn, UClass *(*)() InWithinClassFn, bool bIsDynamic, void(*)(UDynamicClass *) InDynamicClassInitializerFn) Line 5527 C++ UE4Editor-FMODStudio-0001.dll!UFMODEventControlSection::GetPrivateStaticClass() Line 221 C++ [Inline Frame] UE4Editor-FMODStudio-0001.dll!UFMODEventControlSection::StaticClass() Line 52 C++ UE4Editor-FMODStudio-0001.dll!TClassCompiledInDefer::Register() Line 301 C++ UE4Editor-CoreUObject.dll!UClassRegisterAllCompiledInClasses() Line 805 C++ UE4Editor-CoreUObject.dll!ProcessNewlyLoadedUObjects(FName Package, bool bCanProcessNewlyLoadedObjects) Line 989 C++ [Inline Frame] UE4Editor-CoreUObject.dll!Invoke(void(*)(FName, bool) &) Line 51 C++ [Inline Frame] UE4Editor-CoreUObject.dll!UE4Tuple_Private::TTupleBase>::ApplyAfter(void(*)(FName, bool) &) Line 306 C++ UE4Editor-CoreUObject.dll!TBaseStaticDelegateInstance::ExecuteIfSafe(FName , bool ) Line 731 C++ UE4Editor-Core.dll!TMulticastDelegate::Broadcast(FName , bool ) Line 955 C++ UE4Editor-Core.dll!FModuleManager::LoadModuleWithFailureReason(const FName InModuleName, EModuleLoadResult & OutFailureReason) Line 519 C++ UE4Editor-Core.dll!FModuleManager::LoadModule(const FName InModuleName) Line 353 C++ UE4Editor-HotReload.dll!FHotReloadModule::DoHotReloadInternal(const TMap> & ChangedModules, const TArray> & Packages, const TArray> & InDependentModules, FOutputDevice & HotReloadAr) Line 799 C++ [Inline Frame] UE4Editor-HotReload.dll!FHotReloadModule::RebindPackagesInternal::__l2::::operator()(const TMap> &) Line 1161 C++ [Inline Frame] UE4Editor-HotReload.dll!Invoke(FHotReloadModule::RebindPackagesInternal::__l2:: &) Line 51 C++ UE4Editor-HotReload.dll!UE4Function_Private::TFunctionRefCaller<,void __cdecl(TMap> const &,bool,enum ECompilationResult::Type)>::Call(void * Obj, const TMap> & , bool & , ECompilationResult::Type & ) Line 549 C++ [Inline Frame] UE4Editor-HotReload.dll!UE4Function_Private::TFunctionRefBase,void __cdecl(TMap> const &,bool,enum ECompilationResult::Type)>::operator()(const TMap> & , bool , ECompilationResult::Type) Line 676 C++ UE4Editor-HotReload.dll!FHotReloadModule::CheckForFinishedModuleDLLCompile(EHotReloadFlags Flags, bool & bCompileStillInProgress, bool & bCompileSucceeded, FOutputDevice & Ar, bool bFireEvents) Line 1863 C++ UE4Editor-HotReload.dll!FHotReloadModule::Tick(float DeltaTime) Line 1415 C++ [Inline Frame] UE4Editor-Core.dll!TDelegate::Execute(float) Line 580 C++ [Inline Frame] UE4Editor-Core.dll!FTicker::FElement::Fire(float) Line 127 C++ UE4Editor-Core.dll!FTicker::Tick(float DeltaTime) Line 95 C++ UE4Editor.exe!FEngineLoop::Tick() Line 5132 C++ [Inline Frame] UE4Editor.exe!EngineTick() Line 62 C++ UE4Editor.exe!GuardedMain(const wchar_t * CmdLine) Line 178 C++ UE4Editor.exe!LaunchWindowsStartup(HINSTANCE __* hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow, const wchar_t * CmdLine) Line 262 C++ UE4Editor.exe!WinMain(HINSTANCE __* hInInstance, HINSTANCE__ * hPrevInstance, char * pCmdLine, int nCmdShow) Line 320 C++ [Inline Frame] UE4Editor.exe!invoke_main() Line 102 C++ UE4Editor.exe!__scrt_common_main_seh() Line 288 C++ ``` Note : It happens when hitting “Compile” for the 2nd time. ![image](https://canada1.discourse-cdn.com/flex036/uploads/fmod/original/2X/4/49edb9cd8f443e6e525587cc12546a918ce374b2.png) Any progress in your investigation Jeff ? Best; Mathieu ---
**Author:** ![Tarfax](https://avatars.discourse-cdn.com/v4/letter/t/d9b06d/32.png) [@Tarfax](https://qa.fmod.com/u/Tarfax)\ **Post date:** [February 7, 2023, 6:46pm UTC](https://qa.fmod.com/t/ue4-editor-crashes-when-recompiling-code-vtable-ptr/18619/9 "2023-02-07T18:46:58Z")
If its any help, I suspect it has to do with multi-threading. Also, you get the crash if you’re using Rider. Visual Studio seems to handle this? ---
**Author:** ![jeff\_fmod](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/jeff_fmod/32/1766_2.png) [@jeff\_fmod](https://qa.fmod.com/u/jeff_fmod)\ **Post date:** [February 13, 2023, 1:20am UTC](https://qa.fmod.com/t/ue4-editor-crashes-when-recompiling-code-vtable-ptr/18619/10 "2023-02-13T01:20:21Z")
Thank you for the additional information, I have reproduced this issue now. There appears to be an issue with the `OnEventStopped`, `OnTimelineMarker` and `OnTimelineBeat` callback delegates. I have found that removing them from the FMODStudio plugin allows hot reloading to succeed without issue. I have passed this onto the Dev team to fix in a future release. In the meantime, presuming you won’t be needing those callbacks in the immediate future, you can do the following to get back to a working state: 1. Delete the “ **Plugins\FMODStudio\Intermediate** ” directory 2. Comment out `OnEventStopped`, `OnTimelineMarker` and `OnTimelineBeat` from “ **Plugins\FMODStudio\Source\FMODStudio\Classes\FMODStudioComponent.h** ” ```diff //FMODAudioComponent.h ~Line 103 /** Called when an event stops, either because it played to completion or because a Stop() call turned it off early. */ + //UPROPERTY(BlueprintAssignable) + //FOnEventStopped OnEventStopped; /** Called when we reach a named marker (if bEnableTimelineCallbacks is true). */ + //UPROPERTY(BlueprintAssignable) + //FOnTimelineMarker OnTimelineMarker; /** Called when we reach a beat of a tempo (if bEnableTimelineCallbacks is true). */ + //UPROPERTY(BlueprintAssignable) + //FOnTimelineBeat OnTimelineBeat; ``` 1. Comment out references to `OnEventStopped`, `OnTimelineMarker` and `OnTimelineBeat` in “ **Plugins\FMODStudio\Source\FMODStudio\Private\FMODAudioComponent.cpp** ” ```diff //FMODAudioComponent.cpp ~Line 335 void UFMODAudioComponent::EndPlay(const EEndPlayReason::Type EndPlayReason){ ... if (shouldStop) { Stop(); + //OnEventStopped.Broadcast(); } Release(); } ... //~Line 366 void UFMODAudioComponent::TickComponent(float DeltaTime, enum ELevelTick TickType, FActorComponentTickFunction *ThisTickFunction) { ... for (const FTimelineMarkerProperties &EachProps : LocalMarkerQueue) { + //OnTimelineMarker.Broadcast(EachProps.Name, EachProps.Position); } for (const FTimelineBeatProperties &EachProps : LocalBeatQueue) { + //OnTimelineBeat.Broadcast(EachProps.Bar, EachProps.Beat, EachProps.Position, EachProps.Tempo, EachProps.TimeSignatureUpper, EachProps.TimeSignatureLower); } } ... //~Line 793 void UFMODAudioComponent::OnPlaybackCompleted() { ... if (StudioInstance) { UE_LOG(LogFMOD, Verbose, TEXT("UFMODAudioComponent %p PlaybackCompleted"), this); Release(); // Fire callback after we have cleaned up our instance + //OnEventStopped.Broadcast(); } ... } ``` 1. Comment out references to `OnEventStopped`, `OnTimelineMarker` and `OnTimelineBeat` in “ **Plugins\FMODStudio\Source\FMODStudio\Classes\FMODAudioComponent.h** ” ```diff //FMODAudioComponent.h ~Line 170 /** Called when an event stops, either because it played to completion or because a Stop() call turned it off early. */ + //UPROPERTY(BlueprintAssignable) + //FOnEventStopped OnEventStopped; /** Called when we reach a named marker (if bEnableTimelineCallbacks is true). */ + //UPROPERTY(BlueprintAssignable) + //FOnTimelineMarker OnTimelineMarker; /** Called when we reach a beat of a tempo (if bEnableTimelineCallbacks is true). */ + //UPROPERTY(BlueprintAssignable) + //FOnTimelineBeat OnTimelineBeat; ``` 1. Build your project from Visual Studio After that, hot reloading should behave as expected. With these changes, you can still implement your own [event callbacks](https://fmod.com/docs/2.02/api/studio-api-eventinstance.html#fmod_studio_event_callback_type) in C++, you just won’t be able to do so with blueprints.