Music alias problems - duplicate iTunes Library

Hi Kate876.

The Music app under Catalina is pretty obviously made with the "typical" user in mind. And, as most of the world moves more in the direction of subscriptions and streaming, users like you and I with large libraries of actual files on a drive become less typical. Keep in mind that the library file does not contain any actual media. it is just a data file that describes the location and other metadata of the media files. As such it's not a huge file.

I have seen reports from some users with libraries on an external drive who saw the same alias and removed it and those reports have generally said that doing so has caused duplicate listings for all or most songs in the user's library. Apple has not published any advice on this to date, but based on reports from other users, my advice would be:

1) Leave that alias on the SD card which houses your main library alone.

2) Get rid of the library on the NAS unless it is just used as a backup.

If you only need to access the library when the iPhone 8 is on the same Wi-Fi network as the Mac, you can use Home Sharing without incurring any costs.

Use Home Sharing to share media from a computer to other devices - Apple Support

If you are trying to use the iPhone to access the library via cellular data or when on a different Wi-Fi network, then the Sync Library function using either the Apple Music service or iTunes Match are more reliable solutions.

Cheers.

Hello Kate876 and welcome to Apple Support Communities.

I see you're having an issue with duplicate iTunes library files.

Are you running macOS Catalina with the new Music app or are you running an older version of macOS that still uses iTunes?

You can determine this by looking at the library file that has been created on the Mac. If the file type is .itl (iTunes Library) then it's iTunes. If the file type is .musiclibrary, then you're running Catalina.

Catalina expects the library and media files to be on the internal drive.If you are going to continue to try to have your media and library files on two different external devices then the best way to deal with it is to do nothing with the files and every time you open iTunes or Music, do so with the Option key held down and you'll be given an option of which library to open.

Also, if you decide to go the virtual route, you actually can use iCloud Music Library or Sync Library (again, depending on if you're running iTunes or the Music app). One feature of the Apple Music service is that it matches the content in your library with what's available in the iTunes Store and anything not available is uploaded so you can access it from any device signed in to the same Apple ID. You can also use iTunes Match to accomplish the same thing.

iTunes Match - Apple Support

Cheers.

Hi Kate876.

If you decide to go the Apple Music route and have a large number of songs that were added to your library from CDs or other sources that are not iTunes purchases, it's important to have a backup in case things go awry with the Sync Library feature. That fact is called out specifically in Apple's documentation on the feature.

"Apple Music isn't a back up service. Make sure to back up your iPhone, iPad, iPod touch, Mac, or PC, so that you have a copy of your music and other information in case your device is ever replaced, lost, or damaged."

Turn on Sync Library with Apple Music - Apple Support

Cheers.

Hi Kate876.

Glad to be able to help get you on a path towards resolving this. Have a brilliant rest of your day.

Cheers.