Larry, I had a similar pro

Larry, I had a similar problem when Vegas was first released and I added fill light effect or a couple others. I don’t necessarily believe it was Vegas causing this, I think it was the video card as when I went to CPU only it didn’t happen. I have not had the problem since my GPU drivers have been updated a few times as well as a couple vegas updates. Maybe the newer build is not playing nice with the drivers.. try CPU only?