Unreal 4.9 Mobile Preview and Standalone Preview crash

Development Platform & Builds Mobile
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1

Hi All,

I am working on a mobile game in 4.7.6 without any problems, recently i wanted to take advantage of some mobile features and upgraded to 4.9. I noticed that the mobile and standalone previews crash however running in selected viewport works just fine. All of the blueprints compile fine. I am somewhat at a loss, I have googled this and nothing is really helping. Thanks in advance.

Unknown exception - code 00000001 (first/second not available)

"Assertion failed: IsInGameThread() || IsInAsyncLoadingThread() [File:D:\BuildFarm\buildma

UE4Editor_Core!FDebug::AssertFailed() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\core\private\misc\outputdevice.cpp:354]
UE4Editor_Engine!FRawDistributionFloat::Initialize() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\distributions.cpp:889]
UE4Editor_Engine!FRawDistributionFloat::GetValue() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\distributions.cpp:911]
UE4Editor_Engine!FParticleBeam2EmitterInstance::FillReplayData() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\particles\particlebeam2emitterinstance.cpp:1516]
UE4Editor_Engine!FParticleBeam2EmitterInstance::GetDynamicData() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\particles\particlebeam2emitterinstance.cpp:1249]
UE4Editor_Engine!UParticleSystemComponent::CreateDynamicData() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\particles\particlecomponents.cpp:3211]
UE4Editor_Engine!UParticleSystemComponent::UpdateDynamicData() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\particles\particlecomponents.cpp:3316]
UE4Editor_Engine!UParticleSystemComponent::SendRenderDynamicData_Concurrent() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\particles\particlecomponents.cpp:2935]
UE4Editor_Engine!UActorComponent::DoDeferredRenderUpdates_Concurrent() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\components\actorcomponent.cpp:1209]
UE4Editor_Engine!::operator()() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\leveltick.cpp:835]
UE4Editor_Engine!FParallelForData::Process() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\core\public\async\parallelfor.h:71]
UE4Editor_Engine!TGraphTask::ExecuteTask() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\core\public\async\taskgraphinterfaces.h:797]
UE4Editor_Core!FTaskThread::ProcessTasks() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\core\private\async\taskgraph.cpp:539]
UE4Editor_Core!FTaskThread::ProcessTasksUntilQuit() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\core\private\async\taskgraph.cpp:340]
UE4Editor_Core!FTaskThread::Run() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\core\private\async\taskgraph.cpp:690]
UE4Editor_Core!FRunnableThreadWin::Run() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\core\private\windows\windowsrunnablethread.cpp:74]

2

There is something wrong with a particle system.

Was this error printed?

Somehow Distribution %s wasn’t dirty, but its FRawDistribution wasn’t ever initialized!

If so, I would resave whatever assets it mentions.

There is a workaround, the console variable “AllowAsyncRenderThreadUpdates” can be set to 0.

I would love to know how this happens, so any clues would be appreciated.

3

There is something wrong with a particle system.

Was this error printed?

Somehow Distribution %s wasn’t dirty, but its FRawDistribution wasn’t ever initialized!

If so, I would resave whatever assets it mentions.

There is a workaround, the console variable “AllowAsyncRenderThreadUpdates” can be set to 0.

I would love to know how this happens, so any clues would be appreciated.

4

Hi Gil, Thanks for the quick response. That error is not printed at the time of the crash. I also looked through the crash (Diagnostics.txt and Game.log) and I don’t see that error either.

5

Today I also migrated the game to Unreal 4.8.3 and that migration was successful. I could play the game just fine using the Mobile Preview. I went ahead and upgraded the 4.8.3 version of the game to Unreal 4.9 and the same issue happened again (the Mobile Preview crashed), I was hoping migrating to 4.8.3 might help before migrating to 4.9.

6

Update: Based on your suggestion that the particle system is the problem. I went ahead created a simple map with each particle I was using. I found the particle system that’s causing it to crash. Do you know if there is any link to any documentation on breaking changes on particle systems between 4.8.3/4.7.6 and Unreal 4.9?

7

We should have this fixed soon. It isn’t a breaking change, so much as we enabled some parallel code that apparently crashes with some particle systems. It is a bug.

The workaround you need to use now is to adjust your console variables with:
AllowAsyncRenderThreadUpdates 0

8

Thanks Gil, looking forward to the next update which hopefully will have the fix. In the mean time, I will try the console variable approach, thanks for suggesting that.

9

Hey ,

I wanted to let you know that we’ve submitted a fix for this, it should be implemented in the near future.

Have a great day!