Welcome to the forums, Martin! The latest builds for the 2019 version is 325, and for the 2020 version 423. They can be downloaded and installed from here: https://www.pgmusic.com/support_macintoshupdates.htm

When you say that the message doesn't appear if you play the song first, do you mean the regular play button or the re-generate and play button (play with a + sign)? Tracks need to be re-generated before they can be exported/rendered.


Best,
Chantelle