Video enhance version 3 continuous looping

I have decided to try version 3 (at last!!) after happily using version 2.6.4 for some time. I am trying to enhance a small clip using v3004b. The clip seems to have processed but there is no length quoted, so I know that it hasn’t completed properly and won’t seek. The preview (side by side) is looping continuously (the clip is only 01.54.20 long.)
I am performing a x2 enhance using Artemis, but the problem is the same whatever I do. I am assuming that the export/save starts the process, as I can’t find any instructions for v3 (are there any?).
I know that I must be doing something wrong that’s very simple, but can’t spot it.