Mark: Thanks. I've started on the checklist [and I've been using Carrara 4.3]

On the re-sizing issue, I know about repeat duplicating and objects inheriting properties...and use it often. In this case, there was no re-sizing happening at all. I was just duplicating cylinders & elbows to build a network of pipes.

I just put in a long day today building the base, and none of these problems have cropped up. Of course. I've closed out of Carrara about three or four times, for various reasons. [Like launching Photoshop...which freezes if I launch it with Carrara already open.] Closing the app. seems to solve Carrara's problems with itself. But I'll keep you posted.