There is currently an issue with Vegas 13 during the archiving process. A new message box prompt is shown during the archive process. It means you need to click OK for every video.
I'm looking into a workaround but if you're thinking of upgrading, I'd stick with an older version.
The Sony Vegas message is "“Some of the media on the timeline was not trimmed to preserve quality.” It can be ignored but it's annoying.
Mick