Lightning Build Failed. Swarm Failed to Kick off

Yes I deleted a whole section of the map, built lighting, and it worked. Oddly enough, after I restarted the project without saving in order to recover the section of the map I deleted, I built the lighting again without deleting any meshes and it built just fine.

So apparently there was no corrupt mesh that was preventing lighting from building. Just an error with a mesh on the map, which fixed itself after temporarily deleting it.