Lighting build crash

Here is my project setup:

As you can see I have setted up a lightmass importance volume and the stage is pretty small , with only 2 lights:

Error <None> === Lightmass crashed: ===
Fatal error: [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.7\Engine\Source\Programs\UnrealLightmass\Private\Lighting\LightingSystem.cpp] [Line: 1324] 
Static lighting thread exception:
Fatal error: [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.7\Engine\Source\Runtime\Core\Private\GenericPlatform\GenericPlatformMemory.cpp] [Line: 54] 
Ran out of memory allocating 16384 bytes with alignment 0


KERNELBASE.dll!UnknownFunction (0x000007fefcb3940d) + 0 bytes [UnknownFile:0]
UnrealLightmass-Core.dll!UnknownFunction (0x000007fec70444f4) + 0 bytes [UnknownFile:0]
UnrealLightmass-Core.dll!UnknownFunction (0x000007fec6f22754) + 0 bytes [UnknownFile:0]
UnrealLightmass-Core.dll!UnknownFunction (0x000007fec6e37867) + 0 bytes [UnknownFile:0]
UnrealLightmass-Core.dll!UnknownFunction (0x000007fec6e33ebd) + 0 bytes [UnknownFile:0]
UnrealLightmass.exe!operator new<TChunkedArray<Lightmass::FTexelToCorners,16384>::FChunk,FDefaultAllocator>() (0x000000013fc6793a) + 0 bytes [UnknownFile:0]
UnrealLightmass.exe!Lightmass::FTexelToCornersMap::FTexelToCornersMap() (0x000000013fc8085d) + 0 bytes [UnknownFile:0]
UnrealLightmass.exe!Lightmass::FStaticLightingSystem::ProcessTextureMapping() (0x000000013fd369a5) + 0 bytes [UnknownFile:0]
UnrealLightmass.exe!Lightmass::FStaticLightingSystem::ThreadLoop() (0x000000013fcee9d7) + 0 bytes [UnknownFile:0]
UnrealLightmass.exe!Lightmass::FMappingProcessingThreadRunnable::Run() (0x000000013fce5639) + 0 bytes [UnknownFile:0]
UnrealLightmass-Core.dll!UnknownFunction (0x000007fec7043b16) + 0 bytes [UnknownFile:0]
UnrealLightmass-Core.dll!UnknownFunction (0x000007fec703800d) + 0 bytes [UnknownFile:0]
kernel32.dll!UnknownFunction (0x0000000076ae59ed) + 0 bytes [UnknownFile:0]
ntdll.dll!UnknownFunction (0x0000000076d1c541) + 0 bytes [UnknownFile:0]
ntdll.dll!UnknownFunction (0x0000000076d1c541) + 0 bytes [UnknownFile:0]

Oh and a windows out of ram message pops up for UnrealLightmass(I have 8 gigs of ram and an ssd + hdd installed)

By chance a friend I tutored today also had this issue.
We bypassed it by making any lightmap that was 4096 in resolution 2048.

also, be sure to check the following:
He ran out of memory.
Maybe your hard drives are full, make them not full
If everything seems normal, see if you turned off his virtual memory, if you did… turn them back on. (some advice Allar gave him)

his first error:

http://public.capable.ch/xl2piu/20150405161018.png

his second error after reboot of ue4:

http://public.capable.ch/xl2piu/20150405161355.png

I am assuming its some weird bug from 4.7.4.

I’m posting here since I ran into the exact same problem today. Running UE 4.7.4, Windows 7 64 bit. I’m the friend Luos referred to.

I’ve had cases where Windows did indeed also warn about low ram, but I’ve also encountered the exact same problem where Windows did not warn me and I was at 6-7/12GB of ram at the moment of UnrealLightmass crashing.

Hopefully this can be fixed.

A temp solution for me is closing down a lot of running applications to get my ram usage as low as possible, and turning some lightmass texture sizes for meshes lower. Restarting UE Editor has also seemed to somewhat improve my chances.