I think I may have figured out what causes some of Terragen's lockups when doing things like "Saving as" or importing an object and such. I was watching a couple freezes today and notice that they all solve themself with the RTP saying "Preview finished". So I did a test and made a change, timed the RTP at 42 seconds, and than did a save as after making another change. The freeze took 42 seconds. Hmm go figure.