Gebe, During the time betweeen when I posted this and just 2 minutes ago, I ran some other experiments to try to isolate the cause of the problem. The fist thing I tried after the above two failures was to try a small preview render, and save it to disk, to see if that was the problem. The glow still worked there. Then I went back to final render settings, but kept the size small. No glow. Tried a few more things, but the long and short of it was indeed lack of memory. After giving up for a couple of hours and leaving the computer off during that time, I rebooted and tried again. This time success. I guess the moral of the story is always shut-down the computer before attempting to render a large production image. The weird thing is, I wasn't even considering that it was a lack of memory, because the render progress screen was reporting a finished render. But anyways, thanks so much for your reply. Just in reading these boards, I can tell that you are one of the most responsive mods I've ever seen, and that you seem to do it out of the pure passion you have for this software and the community. If Rendo ever has a Mod of the Year competition, my vote would lie with you! (G:`,