I went to back up a single episode of Highlander (previously ripped to HD) from one of my season discs using the latest preview and CloneDVD wouldn't proceed because it said I didn't have enough space free. The episode I wanted to back up was about 2.5 gig total and CloneDVD wanted about 8 gig free (the size of the whole season disc). Each episode is stored in its own unique VOB on the season disc.
I tried the latest official release and it worked fine with less than 8 gig free on the HD. A bug in the preview version?