Working on a project which was working fine until recently. After some adjustments with geometries and lighting, as soon as the light building completes I get the following error message
I tried making the lightmass volume a bit bigger but no luck
Nothing like a nice forum answer a year after the fact, but I was having the same issue. No answers anywhere, and no way to contact any kind of real Unreal support, so I had no choice but to keep clicking through the endless menus and drop downs in unreal until I came across something kind of obvious.
Under World settings, Lightmass, I saw that there was one of those yellow arrows indicating that something had been changed from the default and could be changed back (brilliant feature!) I clicked on that arrow next to ‘lightmass settings’ resetting that to default, then did a lighting build. No problem. NO more Divide by Zero error. No failure. I hope this helps you or anyone else who comes across this.