UE 5.5 SlateRHI Headless Rendering Crash on Viewport Resize

Development Rendering
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Since version 5.5 we’ve been seeing the crash above when rendering remotely on a render farm in some projects (Meerkat). A very similar callstack in 5.4 shows as a Handled Ensure and continues to render successfully.

Unreal was launched with the following options:

Starting Unreal Engine with args: [‘UnrealEditor-Cmd’, ‘C:\\ProgramData\\Amazon\\OpenJD\\session-08d07b6531894df6a8306f4e0b2d54d9ioppj78b\\assetroot-1b3849b96ef425885142\\MeerkatDemo55.uproject’, ‘-log’, ‘-unattended’, ‘-stdout’, ‘-allowstdoutlogverbosity’, ‘-nozen’, ‘-NoLoadingScreen’, ‘-NoScreenMessages’, ‘-RenderOffscreen’, ‘-FixedSeed’, ‘-deterministicaudio’, ‘-epiclocale=en’, ‘-audiomixer’, ‘-epicapp=UE_5.5’, ‘-EpicPortal’, ‘-AUTH_LOGIN=unused’, ‘-dpcvars=“sg.ViewDistanceQuality=4,sg.AntiAliasingQuality=4,sg.ShadowQuality=4,sg.GlobalIlluminationQuality=4,sg.ReflectionQuality=4,sg.PostProcessQuality=4,sg.TextureQuality=4,sg.EffectsQuality=4,sg.FoliageQuality=4,sg.ShadingQuality=4,r.TextureStreaming=0,r.ForceLOD=0,r.SkeletalMeshLODBias=-10,r.ParticleLODBias=-10,foliage.DitheredLOD=0,foliage.ForceLOD=0,r.Shadow.DistanceScale=10,r.Shadow.RadiusThreshold=0.001000,r.ShadowQuality=5,r.ViewDistanceScale=50,r.D3D12.GPUTimeout=0,r.Streaming.SyncStatesWhenBlocking=1,GeometryCache.Streamer.BlockTillFinishStreaming=1,GeometryCache.Streamer.ShowNotification=0,a.URO.Enable=0,au.NeverMuteNonRealtimeAudioDevices=1,r.SkyLight.RealTimeReflectionCapture.TimeSlice=0,r.VolumetricRenderTarget=1,r.VolumetricRenderTarget.Mode=3,wp.Runtime.BlockOnSlowStreaming=0,p.Chaos.ImmPhys.MinStepTime=0,r.SkipRedundantTransformUpdate=0,p.ChaosCloth.UseTimeStepSmoothing=0,r.Water.SkipWaterInfoTextureRenderWhenWorldRenderingDisabled=0,r.Nanite.VSMInvalidateOnLODDelta=1”’, ‘-epicenv=Prod’, ‘-epicsandboxid=ue’, ‘-AUTH_TYPE=exchangecode’, ‘-AUTH_PASSWORD=<…>’, ‘-epicuserid=<…>’, ‘-MRQInstance’, ‘-Unattended’, ‘-epicusername=azbaxe’, ‘-execcmds=r.HLOD 0,py C:/Program Files/Python312/Lib/site-packages/deadline/unreal_adaptor/UnrealClient/unreal_client.py’]

Attached dxdiag and crashreportclient.txt.

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Hey there! This looks like a crash were seeing with a similar call stack, can you try integrating this changelist?

CL#42231340 (c0e6083) crash fix when resizing window resolution with -renderoffscreen (UE 5.6)

Related public issue:

https://issues.unrealengine.com/issue/UE-276282 Crash when changing window resolution with AMD GPU, D3D11 and renderoffscreen

Also, I’m noticing your CVars on the command line include those for DX12, but your call stack is for DX11. If your crash is DX11 then the above fix should work, but if you’ve switched to DX12 that CL will not have any effect.

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This does indeed seem to fix it!

I’ll have to go back and retest with DX12 - I believe that was one of the first fixes we tried initially and I thought we saw the same or a fairly similar callstack. Looks like there may be some old CVar settings still left from that attempt.

Thanks!

4

I’ve also tested again with DX12 successfully - Looks like this fix might have fixed the other issue we were seeing.

Thanks again!