Yes, it could be taking time to check every temporary file that the render process is creating. Try disabling it and render again.
To expand on what John said, this is an old gotcha’ in Vegas, and those of us who have been bit by this one learn to see it on the timeline. Note the thin white line at the top of the event below. As john said, this will turn a 30 minute render into a 6-hour one because every pixel in every frame needs to be rendered.

Vegasaur has an audit tool that will highlight this. I run it before every final render:

Steve Mann
MannMade Digital Video
http://www.mmdv.com