Gen Not Working: Vray Light

V-Ray Light Gen, in some versions, fails to write temporary HDRI preview files to a path containing a space. It silently fails. No error. Just a dead, dark dome.

It was 2 AM. Alex had a villa exterior due in 12 hours. The client wanted "dramatic, cinematic sunset lighting." vray light gen not working

Alex thought, "No problem. I'll use V-Ray Light Gen. Click a preset. Done." V-Ray Light Gen, in some versions, fails to