1. Open the Music app.
2. In the menu bar, click on Music > Preferences.
3. Select the General tab.
4. In the Default Media Player section, click on iTunes.
5. Quit and reopen the Music app to apply the change.
On Windows
1. Open the Settings app.
2. Click on System.
3. Select Default apps.
4. Scroll down to the Music Player section and click on the app currently set as default.
5. Select iTunes from the list of apps.
6. iTunes will now be set as your default music player.