[MacDV] forcing iMovie to display the dialog ["Your movie contains still, slow motion, and/or reverse clips which need to be rendered for this export. This will provide the best quality. Would you like to render them now?] again

[Mike Rehbein]

When iMovie asks "Your movie contains still, slow motion, and/or  
reverse clips which need to be rendered for this export. This will  
provide the best quality. Would you like to render them now?"
The responses are "Proceed Anyway", "Cancel", "Render and Proceed".

The impression is that iMovie will do the better job of rendering. Not  
true of course, iDVD will.
So click each time this displays "Proceed Anyway".

If the "Render and Proceed" button is clicked just once, this dialog  
never displays again to give you the option of letting iDVD do the  
rendering.

To have iMovie display the dialog again, the com.apple.iMovie.plist  
file needs to be deleted.

Search for it and delete it.

Or you can navigate to it at Users/<your user name>/Library/ 
Preferences/com.apple.iMovie.plist

Mike