Crash after short time of demorec

Development Platform & Builds
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After starting a demo with “demorec name”, approximately 50 seconds later game crashes. This happens when running in standalone mode on default FPS blueprint game.

Access violation - code c0000005 (first/second chance not available)

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UE4Editor_CoreUObject!FSerialNumberManager::GetAndAllocateSerialNumber() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\coreuobject\private\uobject\weakobjectptr.cpp:107]
UE4Editor_CoreUObject!FWeakObjectPtr::operator=() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\coreuobject\private\uobject\weakobjectptr.cpp:202]
UE4Editor_Engine!UNetDriver::FindOrCreateRepChangedPropertyTracker() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\networkdriver.cpp:2810]
UE4Editor_Engine!UDemoNetDriver::TickDemoRecord() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\demonetdriver.cpp:937]
UE4Editor_Engine!UDemoNetDriver::TickDispatch() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\demonetdriver.cpp:458]
UE4Editor_Engine!TBaseUObjectMethodDelegateInstance<0,UNetDriver,void __cdecl(float)>::ExecuteIfSafe() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:772]
UE4Editor_Engine!TBaseMulticastDelegate<void,float>::Broadcast() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:1031]
UE4Editor_Engine!UWorld::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\leveltick.cpp:1094]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\unrealed\private\editorengine.cpp:1339]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\unrealed\private\unrealedengine.cpp:366]
UE4Editor!FEngineLoop::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\launchengineloop.cpp:2355]
UE4Editor!GuardedMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\windows\launchwindows.cpp:200]
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Hi uunx,

Thanks for report! I can confirm that this crash occurs in 4.8.3, but it appears to be fixed in our internal build that will eventually be 4.10. I attempted to test in 4.9, but a separate crash with demorec is currently preventing that investigation (UE-19673). I will re-check this issue as soon as other is resolved and update you here. Thanks again!

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Thanks for update!

Is there a way to take a look at details of UE-19673 bug? Or any temporary fixes?

I have been testing with 4.9 and noticed bug is gone from there, however, if anything which has a “Character” as it’s parent is present (other than playing character) it crashes. Demo recording works if there are no other characters in level however. That’s at least what I’ve found from trying to narrow down source of problem, wondering if anyone else has gone deeper and found any possible fixes or workarounds I could use.

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We don’t have our bug report system public, though we’re planning to do so at some point in future. For now, you can ask us here and we’ll take a look. For this one, I was able to reproduce crash so I included all crash data and steps to reproduce it. I’ll add a note with what you found with Characters, thanks!

For now, I don’t know of any workaround, but I’ll let you know if I can find any.