It was 2 AM. Alex had a villa exterior due in 12 hours. The client wanted "dramatic, cinematic sunset lighting."

If you are using V-Ray GPU, check your VRAM usage. If your scene already uses 90% of your GPU memory, Light Gen will fail. Try purging unused assets or using "On-Demand Mipmap" in the global switches to free up memory before launching Light Gen.

This is a frustrating moment for any 3D artist. Let me tell you a short, relatable story about this exact problem, then give you the most likely fix.

If you have reached step 5 and Light Gen is still dead, capture a screenshot of the error and post it on the official Chaos Group forums—but include your vraylog.txt file. Without the log, they can't help you.