[Mac, UE4.8.1] Engine crash on every hot reload

Hi all,

I previously thought this might have been caused by something in my code, but I’ve tried commenting the whole lot out and still it happens.

I have been experiencing this crash ever since version 4.8.1 as far as I can recall, and I’ve tried many things, including deleting the Intermediate and Saved directories inside my projects, clearing the Derived Data Cache and removing blueprint assets.

It’s an annoyance more than anything, as the compile seems to work. After I restart the engine after the crash my code runs perfectly. The stack trace is below, which has come out pretty much identical for every crash (and there have been a lot!)

Hopefully someone can clarify if this is a bug or make any suggestions as to something I might be doing wrong.

FOutputDeviceMacError::Serialize(wchar_t const*, ELogVerbosity::Type, FName const&) Address = 0x107af4d2f (filename not found) [in UE4Editor-Core.dylib]
FOutputDevice::Logf(wchar_t const*, ...) Address = 0x107bb7def (filename not found) [in UE4Editor-Core.dylib]
FDebug::AssertFailed(char const*, char const*, int, wchar_t const*, ...) Address = 0x107b8a794 (filename not found) [in UE4Editor-Core.dylib]
FBlueprintEditorUtils::PostDuplicateBlueprint(UBlueprint*) Address = 0x10f7311af (filename not found) [in UE4Editor-UnrealEd.dylib]
StaticDuplicateObjectEx(FObjectDuplicationParameters&) Address = 0x1084add28 (filename not found) [in UE4Editor-CoreUObject.dylib]
StaticDuplicateObject(UObject const*, UObject*, wchar_t const*, EObjectFlags, UClass*, EDuplicateForPie) Address = 0x1084ac956 (filename not found) [in UE4Editor-CoreUObject.dylib]
ProcessNewlyLoadedUObjects() Address = 0x108498258 (filename not found) [in UE4Editor-CoreUObject.dylib]
TBaseStaticDelegateInstance::ExecuteIfSafe() const Address = 0x108388ba7 (filename not found) [in UE4Editor-CoreUObject.dylib]
TBaseMulticastDelegate::Broadcast() const Address = 0x1079b2430 (filename not found) [in UE4Editor-Core.dylib]
FModuleManager::LoadModuleWithFailureReason(FName, EModuleLoadResult&, bool) Address = 0x107bedb5f (filename not found) [in UE4Editor-Core.dylib]
FModuleManager::LoadModule(FName, bool) Address = 0x107bec62e (filename not found) [in UE4Editor-Core.dylib]
FHotReloadModule::DoHotReloadInternal(bool, ECompilationResult::Type, TArray, TArray, FOutputDevice&) Address = 0x119c12967 (filename not found) [in UE4Editor-HotReload.dylib]
FHotReloadModule::DoHotReloadCallback(bool, ECompilationResult::Type, TArray, TArray, FOutputDevice&) Address = 0x119c1244b (filename not found) [in UE4Editor-HotReload.dylib]
_ZN21TMemberFunctionCallerI16FHotReloadModuleMS0_FvbN18ECompilationResult4TypeE6TArrayIP8UPackage17FDefaultAllocatorES3_I5FNameS6_ER13FOutputDeviceEEclIJRbRS2_RKS7_RKS9_SB_EEEDTclpmdtdefpT3ObjdtdefpT9MemFunPtrspcl7ForwardIT_Efp_EEEDpOSM_ Address = 0x119c2a557 (filename not found) [in UE4Editor-HotReload.dylib]
TBaseRawMethodDelegateInstance, TArray, FOutputDevice&>::ExecuteIfSafe(bool, ECompilationResult::Type) const Address = 0x119c2a45c (filename not found) [in UE4Editor-HotReload.dylib]
FHotReloadModule::CheckForFinishedModuleDLLCompile(bool, bool&, bool&, FOutputDevice&, bool) Address = 0x119c09c47 (filename not found) [in UE4Editor-HotReload.dylib]
FHotReloadModule::Tick() Address = 0x119c08863 (filename not found) [in UE4Editor-HotReload.dylib]
UEditorEngine::Tick(float, bool) Address = 0x10eb007b4 (filename not found) [in UE4Editor-UnrealEd.dylib]
UUnrealEdEngine::Tick(float, bool) Address = 0x10f1b26ec (filename not found) [in UE4Editor-UnrealEd.dylib]
FEngineLoop::Tick() Address = 0x1078bc2f3 (filename not found) [in UE4Editor]
GuardedMain(wchar_t const*) Address = 0x1078c2df3 (filename not found) [in UE4Editor]
-[UE4AppDelegate runGameThread:] Address = 0x1078d2583 (filename not found) [in UE4Editor]
-[FCocoaGameThread main] Address = 0x107a583ce (filename not found) [in UE4Editor-Core.dylib]
Unknown() Address = 0x7fff88805d8b (filename not found) [in Foundation]
_pthread_body Address = 0x7fff82eb4899 (filename not found) [in libsystem_pthread.dylib]
_pthread_struct_init Address = 0x7fff82eb472a (filename not found) [in libsystem_pthread.dylib]

Hey DarwinLives-

Can you post the log files from the crash as well? Also, does a new project crash when you try to hot reload code added to it? If it’s possible could you send us a stripped down version of your project or a sample project where this crash is occurring?

Cheers

Hey ,

No, it’s something that’s in my project that’s causing it. Here are the log files for the last few crashes today, if that helps. The critical error in most cases seems to be this, but I’m not completely sure what this means.

Assertion failed: Blueprint->GeneratedClass != NULL

I’m seeing a lot of console spam for something called SlugSkeletalMesh not having a skeleton, which is odd as I haven’t got anything by that name, at least not anymore. Could it be trying to reference an old name for a UPROPERTY?

Thanks in advance!

Many of the errors seem to be from missing assets. If you’ve moved/deleted/renamed assets in the content browser or have changed the hierarchy of folders you may need to clean up redirectors to make sure “ghost” objects aren’t being called. You can do this by selecting the Content heading of the content browser and right clicking and selecting “Fix Up Redirectors in Folder”.

I’ve done this – there were a couple of references to old objects which were deleted, but the engine is still crashing on every compile unfortunately.

I’ve also cleaned up some of my code so as to rid myself of some of the console spam, here’s a more recent log file

Hi DarwinLives,

Sorry for the delay in responding to your post. Do you still see this crash occurring in 4.8.2? Do you still see references to SlugSkeletalMesh in the console (the latest set of information you provided does not seem to mention that)?

Having looked over the information provided so far, we are not sure that this is something that is specific to Mac. Have you had any opportunity to see if the same crash occurs on a Windows machine?

Hi DarwinLives,

We have not heard back from you for a few days. Do you still need help with this issue? I will be marking this post as resolved for internal tracking purposes, but if you still need any assistance please feel free to add a comment at any time and re-open the post.