This issue often occurs if the library file was not properly copied, or if Music detects a conflict due to other connected devices, such as an iPhone, iPad, or iPod.
Here are some things you can try:
- Disconnect All Devices - Unplug any iPhones, iPads, iPods, or other devices connected to your Mac. Restart your Mac and ensure no other devices are connected.
- Verify the File Structure on the New External Drive - Make sure you copied the entire Music folder to the new external drive. This folder should include: Media folder (containing all songs, movies, etc.), Music Library file (the database file that organizes your music), and the Previous Libraries folder. Also confirm that the folder structure is identical to what was on the smaller drive.
- Point Music to the new library on the larger drive again - Quit Music. Hold down the Option (Alt) key, and then, launch Music. At the "Choose or Create a Library" prompt, select "Choose Library," and then, navigate to the new library location. Finally, click on "Open."
If the above steps do not help, then:
- Check Permissions on the New Drive to be sure your user account has Read/Write permissions.
- .Turn Off Sync Temporarily - Go to Music > Preferences. Navigate to the General tab and uncheck Sync Library (if it's enabled). Once the new library is loaded, you can enable Sync Library again.
- Sign Out and Back In (If Needed) - Go to Music > Account > Sign Out. Sign back in and reattempt the steps above.
