WHEN YOU USE the Music or TV apps, all of your locally stored content - things you’ve downloaded to your Mac or imported from local files - is stored in a single library. And that’s great, mostly. But sometimes you might want to have more than one library to keep things separate. So, for example, you might not want your home videos alongside your downloaded TV shows, or you might use your Mac for DJ sets and want to keep your deep cuts well away from your guilty pleasures or the kids’ favorites. Perhaps your library is absolutely massive and you want to have a smaller version you can keep on your mobile Mac. Or maybe you want to have different preferences for different libraries so you can apply different display options or parental settings. Whatever the reason, it’s easy to have and switch between different media libraries on your Mac.