I exported a program timeline by reference file. When I bring in the file back into the bin I got a warning saying that the clip has an alpha and only HD mode will handle this. I am not using any alphas. The clip also appears to have a quicktime logo instead of a media 100 logo when locating this in the finder. I am able to export it as a QT DV file and bring it back in (had media 100 logo on clip), but thought this was odd that I was unable to doing this by reference.