I have Vegas Pro 11 (64 bit). I am having an issue rendering some video. All layers and elements look fine but when I render it pops up with some black frames and/or only some of the elements are active in a few frames. I shot and removed a greenscreen (ChromaKey) in some frames. Looks fine most of the way and then bam, a frame or two pops up without the chroma-key removed like it should be and is in most of the video. Not sure whats going on?? I tried all kinds of different settings but no change. 95% of the video is fine. Tried re-rendering many times.
Make sure that you are using the latest version of Vegas Pro 11 Build 701. Unfortunately, Vegas Pro 11.0 was a bit buggy. You may want to download the 30-day free trial of Vegas Pro 12.0 and render your project with that. If it works, you just found an excellent reason to upgrade. ;-)