sigh. trying 2.8.6 now (on OS 9.1), hoping the problem would have gone away, but no luck. incomplete files that apparently Can't be moved to library... not that they're ready to go there anyway.

i've seen it happen to files with no unusual characters in the name (just letters and a dot), and as small as 14MB, so I doubt it's related to size or filename.

thanks to Airhockey for the tip - Kill, switch to Library, Resume. unfortunately it means we've got to babysit the app, but at least we don't have to start over from scratch each time.

ah well - slow, slow progress.