A new Apple support document indicates that the initial public beta release of macOS Catalina doesn’t support switching between multiple iTunes Libraries. The limitation also applies to the first two developer betas of the upcoming Mac operating system.
macOS Catalina betas can only open the previously selected iTunes library on your Mac prior to updating to the beta. Before installing the beta select the iTunes library you want to use by fully shutting down iTunes and then reopening it while holding down the Option key.
Before you install the macOS Catalina Beta, choose the iTunes Library that you want to use on your test computer:
- In the iTunes app on your Mac, choose iTunes > Quit iTunes.
- Hold down the Option key while you open iTunes.
- In the window that appears, Click Choose Library.
The iTunes library that you select will be the open that then opens in the beta versions of the Music, TV, Podcasts apps on macOS Catalina. Those apps replace the iTunes app in the new operating system.
The support document suggests that support for multiple iTunes libraries will return in the public release of Catalina in the fall.
Remember, MacTrast and Apple both warn users to not install any betas on your daily driver Mac computer, instead only install it on a Mac set aside for testing purposes.