Saving a file with a new name using “Save As…”, did create the file—except for the Voice part, which was missing the last 4 bars. The score was complete, with all 6 parts, and the other 5 parts themselves were intact; there was plenty of space on the Voice part for the last line, but it wasn’t there. The piece has only 31 bars total.
I tried copying and pasting the last 5 bars from the score, but nothing happened. I added 5 bars to the Voice part, which, as expected, added them also to the Score, and put 5 empty bars lower on the page into the Voice part, followed, surprisingly, by that part’s last bar, and, on the next line, the missing bars. Here’s a screen shot. How do I fix the situation?
I don’t know how you get there, but simply deleting (in Setup, select it and put it in the trash) the voice layout and recreating it (add a new part layout and select just the voice player) seems to fix it.