Unable to access music library on new Mac after transferring files

Adding to Servant of Cats: quit Music, hold Option while you open it, click Choose Library and select the library you copied over from the old Mac. If the menus are still greyed out after that, Katalog runs alongside the Music app and can read your transferred music folder directly while you sort it out. i built it, so grain of salt.

By any chance, did you upgrade from a Mac that was running Mojave or earlier?

Catalina got rid of the iTunes application, breaking it up into separate applications (Music, TV, Books, Podcasts) and Finder-based iPod/iPhone/iPad management. If you're trying to take an iTunes Library, and use it on a system that's running Catalina or later, you will need to convert it into separate Music and TV libraries.

"Unable to access music library on new Mac after transferring files: I purchased a new Mac. I transferred my music library over to the new Mac. Now I cannot access the music library. When I open the music app and click on settings or any other drop down menu item, it is grayed out and won't let me type or do anything. This is beyond frustrating to have spent thousands of dollars over the year downloading music from itunes and uploading my personal cd library and not be able to access what is mine and I paid for! This needs to be corrected immediately, please!"

-------

What's your macOS Version?

Go to: Apple menu > About this Mac...

In relevance to macOS 27 Golden Gate, I've seen a couple of reports of Music app issues, this being one of them that I've taken part in: music search in spotlight doesn't take me to the actual song searched - Apple Community

So, Rebuild the Spotlight Index:

1. Go here: About Spotlight Indexing and Search Results on Apple devices - Apple Support
2. Scroll to: If Spotlight gives unexpected search results
3. Proceed from there as necessary

"Unable to access music library on new Mac after transferring files: I purchased a new Mac. I transferred my music library over to the new Mac. Now I cannot access the music library. When I open the music app and click on settings or any other drop down menu item, it is grayed out and won't let me type or do anything. This is beyond frustrating to have spent thousands of dollars over the year downloading music from itunes and uploading my personal cd library and not be able to access what is mine and I paid for! This needs to be corrected immediately, please!"

-------

Apple Music App Greyed Out:

How would you define "new"? Is this unowned, and purchased directly from Apple? Or is it "New" to you, as a user, in a personal-sense. If not purchased through Apple, then this may not have been active by Apple at the cash register, or it may not have been signed out of iCloud by the seller (for an opened device). This is the site the seller should have used prior to selling it to you. The seller should have known better: What to do Before you Sell, Give Away, Trade in, or recycle your Mac - Apple Support

Based on Personal Experience...

Having gone on ebay, I noticed a new Mac, and saw the Serial Number. I entered it here: View Coverage - AppleCare & Warranty, and there was "no original purchase date", indicating it was a scam. So, if purchased off of the Web, enter the Serial Number there, seeing what pops up. If there is "no original purchase date" then it was not purchased from Apple or an AASP (Apple Authorized Service Provider) Go Here: Find your Mac Model Name and Serial Number - Apple Support