Developer Notes

Workaround if not on fixed version: The user will need to add a delay after begin play and create his UI at least a frame after BeginPlay.


A player with UMG widget created on BeginPlay works fine when hitting play with only 1 player, but if you set the number of player > 1 it will crash.

User believes this is somewhere related with the setting the owner of the UMG widget.

Steps to Reproduce

1. Extract the zip file attached.
2. Open the Uproject.
3. While in Editor, change number of players to 2 and Play in Editor.
4. Wait for Crash


Error Message: SIGSEGV: invalid attempt to access memory at address 0x3

<unknown module>! CastLogError(wchar_t const*, wchar_t const*)
<unknown module>! ULocalPlayer* CastChecked<ULocalPlayer, UPlayer>(UPlayer*, ECastCheckedType::Type)
<unknown module>! FLocalPlayerContext::SetPlayerController(APlayerController const*)
<unknown module>! UUserWidget* CreateWidget<UUserWidget>(APlayerController*, UClass*)
<unknown module>! UWidgetBlueprintLibrary::execCreate(FFrame&, void*)
<unknown module>! UFunction::Invoke(UObject*, FFrame&, void*)
<unknown module>! UObject::CallFunction(FFrame&, void*, UFunction*)
<unknown module>! UObject::ProcessContextOpcode(FFrame&, void*, bool)
<unknown module>! UObject::execLetObj(FFrame&, void*)
<unknown module>! UObject::ProcessInternal(FFrame&, void*)
<unknown module>! UObject::CallFunction(FFrame&, void*, UFunction*)
<unknown module>! UObject::ProcessInternal(FFrame&, void*)
<unknown module>! UFunction::Invoke(UObject*, FFrame&, void*)
<unknown module>! UObject::ProcessEvent(UFunction*, void*)
<unknown module>! AActor::PostActorConstruction()
<unknown module>! AActor::FinishSpawning(FTransform const&, bool)
<unknown module>! AActor::PostSpawnInitialize(FVector const&, FRotator const&, AActor*, APawn*, bool, bool, bool)
<unknown module>! UWorld::SpawnActor(UClass*, FVector const*, FRotator const*, FActorSpawnParameters const&)
<unknown module>! AGameMode::SpawnPlayerController(FVector const&, FRotator const&)
<unknown module>! AGameMode::Login(UPlayer*, FString const&, FString const&, TSharedPtr<FUniqueNetId, (ESPMode)
<unknown module>! UWorld::SpawnPlayActor(UPlayer*, ENetRole, FURL const&, TSharedPtr<FUniqueNetId, (ESPMode)
<unknown module>! UWorld::NotifyControlMessage(UNetConnection*, unsigned char, FInBunch&)
<unknown module>! UControlChannel::ReceivedBunch(FInBunch&)
<unknown module>! UChannel::ReceivedSequencedBunch(FInBunch&)
<unknown module>! UChannel::ReceivedNextBunch(FInBunch&, bool&)
<unknown module>! UChannel::ReceivedRawBunch(FInBunch&, bool&)
<unknown module>! UNetConnection::ReceivedPacket(FBitReader&)
<unknown module>! UNetConnection::ReceivedRawPacket(void*, int)
<unknown module>! UIpNetDriver::TickDispatch(float)
<unknown module>! TBaseUObjectMethodDelegateInstance<false, UNetDriver, TTypeWrapper<void> (float)
<unknown module>! TBaseUObjectMethodDelegateInstance<false, UNetDriver, void (float)
<unknown module>! TBaseMulticastDelegate<void, float>::Broadcast(float)
<unknown module>! UWorld::Tick(ELevelTick, float)
<unknown module>! UEditorEngine::Tick(float, bool)
<unknown module>! UUnrealEdEngine::Tick(float, bool)
<unknown module>! FEngineLoop::Tick()
<unknown module>! GuardedMain(wchar_t const*)
<unknown module>! -[UE4AppDelegate()
<unknown module>! -[FCocoaGameThread()
<unknown module>! _NSThreadmain_()
<unknown module>! _pthread_body()
<unknown module>! _pthread_body()
<unknown module>! thread_start()

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ComponentUE - Editor - UI Systems
Affects Versions4.7
Target Fix4.8
CreatedFeb 25, 2015
ResolvedApr 30, 2015
UpdatedApr 27, 2018