@JuanP thank you for coming back on this. I've saved the file as you instruct but there's a couple of things that don't make sense to me. Firstly, if my VectorWorks 2019 doesn't support SU2018, then why do you think it will support an even older file? Furthermore, when I save under the new edition, the file type still shows as 2018 at the top. Finally - I've tried to import the '2017' file as you suggest but I'm still getting the same message..trying now with 2016..!