I ran across this problem in earlier betas but neglected to report it.

Anyway, exported AVIs appear to be busted. Media Player Classic gives me a "Cannot render file" error. VLC can't open it either. I tried HandBrake thinking a conversion might get it working, but it says "No valid source or titles found". Happens with all encoding types. MOV export, on the other hand, still works.

This happens in the file I sent previously.