Unable to build lighting in UE5 editor on Linux if level has too many assets

On Linux (I tried it on Elementary OS and Pop!_OS), while on the editor of Unreal Engine 5 (built from source with tag 5.0.1-release), when I try to build lighting of the level, if the scene is too large it fails with the error LightingResults: Error: Import Volumetric Lightmap failed: Expected 256 tasks, only 0 were reported as completed from Swarm. I have not found this issue elsewhere, but I can replicate it on two of my computers.

If I create a small level (with very few objects) it builds the lighting without issues.

I also leave here the full output log of the light building process:

output_log.txt (114.0 KB)

What are your machine specs? If it’s not building larger scenes that usually means you’re out of system resources

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I have the following:

  • AMD Ryzen 7 1700x
  • NVIDIA GTX 1070
  • 64GB of RAM
  • Enough disk space :smiley:
  • I also use swapspace, a software that increases my Swap space dynamically when there is a need.

Note: I noticed that the 5.0.2 had a fix for a bug where the editor could not save files larger than 2GB, I am building the engine on the new version to check if the problem disappears. If not I’ll let you know.

I upgraded to 5.0.2 and I still have this issue. It seems it is not the same issue with storing more than 2GB.

It could be that swapspace isn’t working well enough, in the log at one point it says there’s 819.20 MB RAM budget for shaders, if that’s typical for how it builds shaders that might not mean anything but it could mean that not enough resources are being made available.

Thank you, but I can compile lights just fine on Windows, so that shouldn’t be an issue right?

Windows is the primary platform for UE, so it shouldn’t be surprising that things might not work the same on a different OS. Especially if you’re running other software that’s adjusting system resources.

I understand that but we are no closer to the issue.

The previous log was on a 16GB RAM computer, I try it on the computer with the specs above and even with 64GB RAM and most of it free, the issue still happens. See the logs below.

output_log.txt (118.8 KB)

The issue may be two: Drivers and Distro.
I had the same problem with nouveau on Ubuntu. Killed em all, moved to MX Linux (which is a Debian based distro) with proprietary drivers and that solved my problem. Unfortunately unreal (apart from all bugs this engine has), it seems to have some problems with really-user-friendly distros. Same happened on Mint.