in MacOS Catalina, how does one import an iTunes library into the Music app?

I normally use a different music player app. Basically only use the Music app for Apple Music. But I have been playing around a bit.

I believe I have found a solution to your problem. Basically copy the music from your old to your new Mac (through an external hard disk or big USB stick).

Then :

Press Command + A (Apple key + A) to select all your music. Like I have done by selecting all albums in album view.

Then right click on one of the albums and select Remove from library. Music then asks if you are sure you want to delete them. Select Remove items. And then with the next question choose to keep the files. This will empty the library of Music but keeps all music files on your Mac. Be warned though, if you have an iPad or iPhone and you have your music synced. It will delete the music on the iPad or iPhone.

Now all you need to do next is add your music to Music's library.

This will add all your music to Music's library by choosing Add to library from the File menu. Select the folder where your music is located then press the Open button. Music should now be starting to import all the music from your chosen folder.

Edit:

Maybe also an option is to copy your old Mac's music to a seperate folder. And then just choose to import that folder only. While keeping your original Music library intact.

Good luck :) And let me know if this works for you :)

Hmm. Good question. What happens if you copy the music from your old Mac to your newer one?

Then have a look in Music's preferences and have it add the new music to its collection.

I'm using the Dutch language for my MacOS, but it should be quite easy to find these settings :)

Click on Music on the menu bar -> Preferences -> Files tab :)

I've upgraded to Big Sur, so this is a new version of the Music app. But I'm pretty sure it's the same thing with the Catalina version :)

Good luck :)