Light build failed. Swarm Agent failed to kick off

Have tried building lighting on my level, but it keeps failing, giving the message “Light build failed. Swarm Agent failed to kick off. Compile Unreal Lightmass.” It had worked previously on the level, but now doesnt.

The only error in the message log says “WorldInfo_0 Maps need lighting rebuilt”

I read online it could be a mesh causing this, so i copied all the new meshes over to a blank level where the light build failed. I found after deleting a certain mesh, the build would work. Deleting this one in the main level, the build still fails. Obviously there is the possibility there is another mesh causing this issue that i hadnt copied over. Apart from going through and testing after deleting meshes, can anyone offer any advice?

I am not using the source version, rather the one from the epic website. I’m on version 4.22, i know i should update it, but i started the project in this and have been advised not to migrate it to a newer version.

Everything on my computer is all up to date

Windows 10 64bit
Ryzen 7 1800x
Nvidia GTX 1060 6GB
32Gb 3200Mhz Vengeance Corsair

I have same problem, I start light build, start Swarm 10 second and program crash, help pls

I’ve solved the issue. I have copied things id build from my other levels into it, and for some reason that was creating extra folders and sub folders in my content browser for these meshes. deleting or replacing these has solved it and its building lighting fine

I solved it by using ‘Force no computed lighting’ in world settings. (At least on my smaller level).
… Built it without lightmass then again with.

Helped me a lot. Thank you so much.