If your Mac has multiple partitions running different operating systems, either for dual booting OS X or for Boot Camp, you may decide you want to share the exact same iTunes Library across those different operating systems. This allows you to have the same music library regardless of what OS you’re booted into, and it prevents you from having to carry duplicate songs and media on the same drive.



There are a few ways to go about sharing an iTunes Library like this, but unlike moving the iTunes Media collection to another drive, you can’t simply change the media location within preferences to get it to work (this may be a bug with iTunes 12, that remains to be seen). Instead of going the Preferences route, you can use a little-known trick to force iTunes to either rebuild or reselect a library, and it works flawlessly to share libraries across drive partitions.

Boot into the partition that you want to access the iTunes Media library from (meaning, not the partition where the primary iTunes Library is located) Go to /Applications/ folder and hold down the OPTION key while launching iTunes Select the “Choose Library” button Navigate to the other partitions directory path where the iTunes Media Library is located, it should be something like “/Yosemite HD/Users/OSXDaily/Music/iTunes/” Give iTunes a moment to select the new iTunes Library location, soon it will populate with all of the content, songs, music, and media, from the other partition

You’ll now have the exact same iTunes Library accessible from both partitions and from whatever versions of OS X are running on each. Note that the library location hasn’t changed and has not been moved, it will still be located in it’s original place, which is our intention here. Either operating system can add new music to the iTunes Library as well and it will be accessible from both.

This is particularly helpful if you dual boot and run different versions of OS X on your Mac for testing purposes, or for compatibility with older software that isn’t yet updated for new versions of Mac OS.

Another option is to have an external volume serve as the iTunes Library and have that be the selected media location for all iTunes libraries. That solution works particularly well for managing large iTunes collections on smaller hard drives, since you can offload the entire media library to an external hard drive or USB disk, and still have all the content accessible from your Mac or PC with iTunes.

It’s worth pointing out that each of the OS x versions don’t need to have the same version of iTunes on them, and there is fairly good cross-version compatibility so long as the versions are somewhat modern enough or related to each other.