My main music collection is on OS X Sierra. I just purchased a Nucleus, and added a 2TB SSD as internal storage. My music library doesn’t fit in my Mac’s primary drive, so I have it on a secondary drive /Volumes/Data/Music and $HOME/Music is a symlink to it. iTunes is perfectly happy with this.
The Roon app for Mac doesn’t see the folder at all. Settings/Storage shows “Music Folder” but doesn’t seem to import anything. When I try to add the folder manually, in the “Choose Music Storage Folder” I see no local directories at all, just the “+ Add Network Share” button.
I managed to get files into the Nucleus using SMB to InternalStorage, but it’s not going to be automatically synced with my iTunes library.
One final wrinkle: I don’t want the OS X Roon app to index my entire Music folder, just the iTunes one, and another one holding SACD rips.
I suspect what’s happening is that you are thinking that the “Roon app for Mac” is showing you the storage on your Mac. It isn’t - it’s showing you the storage on your Core - the Nucleus. That “Music Folder” is actually the internal SSD on your Nucleus. You need to add folders on your Mac using the “+Add Network Share” route…
OK, so my mental model for the app is wrong. I was expecting the Mac app to do some sort of peer-to-peer syncing, but in fact it’s just a client and the Core is the one that fetches and sync the music.
Am I correct in understanding Roon will fetch the music over SMB as required, and thus if the Mac is powered off, its music is unaccessible, as it is not automatically copied to internal storage on the Nucleus?