Adding and Removing files in Music Folder

A few days ago, when I initially set up my SonicTransporter i5 , microRendu and Brooklyn DAC, I copied a few files from my NAS drive to the Music folder on my i5’s SSD. Roon found them and played them. But now when I add a file, I see it in the Music folder, but Roon does not see it. And I’ve tried deleting a file from the Music folder. Roon continues to display the album, but when you try to play it there is an error message (of course).

The Music folder is continuously watched by Roon, and I’ve tried Force Rescan but that doesn’t fix the problem. Is there a ‘trick’ to adding/removing files in the Music folder? (I’m on iMac)

Have you tried restarting the ST?

Yes, I did try rebooting the ST. I still see the album that I removed displaying in Roon, but of course I can’t play it. I should be able to freely drag/drop music files into and out of my ST storage (SSD), and Roon should stay in sync - correct?