Thank you for your advice! I was not aware of a newer version -- the 'update' menu did not show it so I assumed I was already at the cutting edge.
The new build also crashed when I tried to import all of the disk filled with lots of music but then I tried importing just one folder at a time (alphabetically ordered, all album titles beginning with A in one folder, etc).
Two folders caused a crash but on re-start and re-try they imported fine and now everything is in order and playing well.
Thanks again!