While conventional internal hard drive space is plentiful in the majority of modern Macs, there are several good reasons why you may wish to store your iTunes Library on an external drive. Firstly, in this day and age, the sheer quantity of media we have in our iTunes Libraries – music, movies, podcasts, apps and more – can threaten to overwhelm our Mac’s internal storage, and modern USB hard drives in capacities measuring in the Terabytes are cheap.

Secondly, while conventional hard drive space is cheap, the rise in SSD or Flash storage such as that seen in the latest MacBook Airs is not, and it may be some time before comparable space on solid state drives is available. Your portable Mac may simply not have enough room to store your full iTunes LIbrary.

The last reason is that if you are running a two Mac system – say a desktop and a laptop – having your iTunes Library on a portable drive means that you can maintain only one Library and access it on both computers.

In the following tutorial, we’ll show you how to move your iTunes media content onto an external drive. Due to the way iTunes likes to catalog your files, it is not as easy as simply dragging and dropping onto the new drive and redirecting the Library path, and some steps need to be taken first.

1.) Go to Applications and open iTunes (alternatively click on its icon in the Dock). Click on iTunes in the Finder Bar and select Preferences:

Selecting iTunes Preferences.png

2.) Click on Advanced. We want to ensure that two options on this page are checked: Keep iTunes Media Folder organized and Copy files to iTunes Media folder when adding to library:

iTunes Advanced Preferences.png

3.) We now need to change the iTunes Media folder location to our external drive. Click Change and navigate to the desired location on the other drive:

Changing the iTunes Library Location to an External Drive.png

4.) Once you have set the new path, press OK to close the iTunes Preferences dialog box.If all your media files in your iTunes Library are already located in your iTunes Media folder, you could simply drag and drop that folder to its new location on the external drive, but the following method of copying the files is preferred to avoid potential conflicts.

If you have added files from other locations on your hard drive – such as the Movies folder – without copying them into the iTunes Media folder by Option (Alt)-Dragging them onto iTunes to create references, you need to consolidate all your files into one place. This is required because iTunes will not copy those files along with the iTunes Media folder if you drag and drop to the new drive, and you may lose the paths in iTunes to those files entirely.

To consolidate your Library and move it to it’s new location at the same time, click on File in the iTunes Finder Bar, navigate to Library and select Organize Library:

Selecting Organize Library in iTunes.png

5.) From the pop-up dialog box, ensure Consolidate files is ticked. If your iTunes Library dates back to a version prior to iTunes 9, you may need to tick Upgrade to iTunes Media organization. If not, that option will be greyed-out, as in the following screenshot:

iTunes Organize Libary Dialog Box.png

6.) Press OK. iTunes may now present you with a dialog box warning you that this cannot be undone. Press Consolidate and iTunes will begin the transfer:

iTunes copying Library files to an External Drive.png

7.) iTunes will now begin copying all your iTunes media files, regardless of their original location, to the new drive. Dependent on how much media you have, this could take a significant amount of time. Once completed, you should be able to see your iTunes Media folder in its new location on your external drive:

The Copied iTunes Media Folder on an External Drive.png

8.) iTunes has only copied the files to the new drive, not moved them, so to free up space on your internal drive, you will need to delete your original iTunes Media folder (not the entire iTunes folder) by dragging it to the Trash and emptying it. Ensure that iTunes recognizes the new location and is working correctly before taking this step. You can check that iTunes is referencing the new iTunes Media folder by Right-Clicking and selecting Get Info on any media file in iTunes, and checking the Where location on the summary page:

iTunes Media File Location Path.png

9.) If you are running a single Mac system, then the process is complete. Note that you will have to have the external drive connected to access any of your previous iTunes content in future. However, you can still use iTunes and download media even if the drive isn’t connected, and incorporate these downloads into your main Library later by following the consolidation procedure outlined above.

If you are sharing the iTunes Library between two Macs, there is a further step. As it stands, while the media content has been moved, your iTunes Library database remains in its original location on the internal drive. This is not an issue for a single Mac system, as the database files take up very little space.

If sharing your Library between two Macs, it is probably best at this point to designate one Mac, say your desktop, as your “primary” iTunes computer. This Mac will handle most of the downloading duties and have the external drive connected to it the majority of the time.

When you want to use your iTunes Library on another Mac, simply drag and drop your iTunes folder from the internal drive of the “primary” Mac to the external drive to copy it. Then, when you connect the drive to the “secondary” Mac, drag the copied iTunes folder to the Music folder on this Mac’s internal drive and click Replace if OS X asks you.

Your Library will now be accessible on the second system. You will need to copy the iTunes folder over every time your Library is updated with new content on the “primary” Mac, as otherwise the Library database on the “secondary” Mac will quickly become outdated and incomplete.