Bill,
I had a similar problem yesterday where I imported about 30 short to longish clips (3 minutes to 30 minutes) and some of them had no audio. I wasn't in a rush so I deleted all the clips from the project and re-imported them. When I did this the conforming bar **never** started. I thought it might be because the project "remembered" them somehow so I started a brand new project and imported the clips. Still no audio in some of them and I'm positive all the clips actually have audio
I am *religious* about copying the entire folder structure (I drive my co-workers nuts about it) and I usually just import clips through Media Browser and walk away for awhile so the conform bar will finish. What is particularly odd is that most of my work is long-format (1 hour+) and I never have this problem with long spanned clips. I have had it a couple of times before and always with short clips. It's never all the clips. Just a random couple here and there. Any ideas?
Camera is a Canon Vixia H300