Lightmass Crash _ Did NOT run out of memory_ Please HELP!

My project was working fine and then this started to happen. I’m trying to find the culprit but I’m not sure where to start. Took out the the scene the meshes and materials i was editing right before it happened but still not working so…I don’t know where to start.

=== Lightmass crashed: ===Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0xffffffff
Fatal error: [File:D:\Build++UE4+Release-4.18+Compile\Sync\Engine\Source\Programs\UnrealLightmass\Private\Lighting\LightingSystem.cpp] [Line: 1338]
Static lighting thread exception:
Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0xffffffff
0x00000000F32D85A2 embree.dll!UnknownFunction ]
0x00000000F2E095F0 embree.dll!UnknownFunction ]
0x000000008E9594EC UnrealLightmass.exe!UnknownFunction ]
0x000000008E927B47 UnrealLightmass.exe!UnknownFunction ]
0x000000008E9BD12A UnrealLightmass.exe!UnknownFunction ]
0x000000008E99A25C UnrealLightmass.exe!UnknownFunction ]
0x000000008E9BFE76 UnrealLightmass.exe!UnknownFunction ]
0x000000008E97E9CB UnrealLightmass.exe!UnknownFunction ]
0x000000008E972D29 UnrealLightmass.exe!UnknownFunction ]
0x00000000ECA5737C UnrealLightmass-Core.dll!UnknownFunction ]
0x00000000ECA47F43 UnrealLightmass-Core.dll!UnknownFunction ]
0x0000000050482774 KERNEL32.DLL!UnknownFunction ]
0x0000000051780D51 ntdll.dll!UnknownFunction ]
0x0000000051780D51 ntdll.dll!UnknownFunction ]
LightingResults: Error: <None> === Lightmass crashed: ===Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0xffffffff
Fatal error: [File:D:\Build++UE4+Release-4.18+Compile\Sync\Engine\Source\Programs\UnrealLightmass\Private\Lighting\LightingSystem.cpp] [Line: 1338]
Static lighting thread exception:
Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0xffffffff
0x00000000F32D85A2 embree.dll!UnknownFunction ]
0x00000000F2E095F0 embree.dll!UnknownFunction ]
0x000000008E9594EC UnrealLightmass.exe!UnknownFunction ]
0x000000008E927B47 UnrealLightmass.exe!UnknownFunction ]
0x000000008E9BD12A UnrealLightmass.exe!UnknownFunction ]
0x000000008E99A25C UnrealLightmass.exe!UnknownFunction ]
0x000000008E9BFE76 UnrealLightmass.exe!UnknownFunction ]
0x000000008E97E9CB UnrealLightmass.exe!UnknownFunction ]
0x000000008E972D29 UnrealLightmass.exe!UnknownFunction ]
0x00000000ECA5737C UnrealLightmass-Core.dll!UnknownFunction ]
0x00000000ECA47F43 UnrealLightmass-Core.dll!UnknownFunction ]
0x0000000050482774 KERNEL32.DLL!UnknownFunction ]
0x0000000051780D51 ntdll.dll!UnknownFunction ]
0x0000000051780D51 ntdll.dll!UnknownFunction ]
*** CRITICAL ERROR! Machine: DESKTOP-GRDBJNT
*** CRITICAL ERROR! Logfile: UnrealLight_DESKTOP-GRDBJNT_D8EB4DCC4F39B33C0F1A708EC5B6B58C.log
*** CRITICAL ERROR! Crash report:
Job has failed! The task failure count is non-zero
LogStaticLightingSystem: Warning: Failed to build lighting!!! Lighting build failed.

You might want to check if you set any lightmaps to be a non square of 2 number, I had that a while back that would always crash lightmass. Think in the statistics view you can see all the lightmaps resolutions together.

Check that your Swarm cache doesn’t contain corrupt data:

  • Open the swarm agent by double clicking the swarm agent icon in the task bar (it may not be visible until you’ve already tried to build lighting).
  • Select Cache | Clean and then Cache | Validate from the menu
  • Check the Log tab to see whether it’s happy.