How to Backup an iPhone to External Hard Drive with Mac OS X

For those of us with larger storage size iPhone and iPad models, backing up the device locally can be a burden on limited disk space. A simple solution to this storage dilemma is to backup an iPhone, iPad, or iPod touch to an external hard drive instead, where disk space is often more abundant. We’ll walk you through how to get this setup in Mac OS X, so that any locally made backup from iTunes goes to an external disk rather than the internal drive, thereby helping to preserve local disk space and offload storage requirements.

In order to successfully get iTunes backups of iOS devices to automatically backup to and store on an external drive, you’ll need some working knowledge of the command line and directory structures, since we’ll be using symbolic links to get this done. Aside from that, you’ll need the usual to make a generic iPhone or iPad backup with iTunes, including a USB cable for the iOS device, and of course an external hard drive with enough free space available to maintain the backups. I personally use the same hard drive for Time Machine and for file storage and created a subfolder on the file storage portion for iOS backups, but you can use a separate drive, a dedicated drive, a partition, or whatever works for you. If you haven’t done so already, be sure to set up Time Machine and complete a backup of the Mac before beginning.

How to Backup iPhone & iPad to an External Hard Drive with Mac OS X

This works the same with all versions of Mac OS X, all types of iOS devices with versions of iOS, and all versions of iTunes, since the location of the iOS backup files has stayed the same on the Mac. Technically you could do this with a network volume as well, but we’re focusing on a traditional external hard disk here.

1. Quit iTunes if you haven’t done so already
2. Connect the external hard drive to the Mac if you haven’t done so already, then create a new folder on the drive (or partition) to dedicate to the iTunes backups. In this example, we’re creating a folder to store the backups called “iTunesExternalBackupSymLink” so that it’s purpose remains obvious
3. Open a new Finder window, then hit Command+Shift+G and enter the following path:

~/Library/Application Support/MobileSync/

4. Locate the folder in this directory called “Backup” and copy that to the folder you just made on the external drive (in this example, the folder called ‘iTunesExternalBackupSymLink’ )
5. Back in the original location of the Backup folder (at ~/Library/Application Support/MobileSync/), rename “Backup” to “Backup-Old”, or simply delete it – only do this after you have copied this folder to the external drive
6. Now launch the “Terminal” application, found in /Applications/Utilities/ and type the following command, changing the names of your external drive and folder as appropriate ,then hit the return key:

ln -s /Volumes/FileStorage/iTunesExternalBackupSymLink/Backup/ ~/Library/Application Support/MobileSync
In this example, the external hard drive is named “FileStorage”, and the iTunes backup folder on that volume is ‘iTunesExternalBackupSymLink’, so adjust those as needed for your situation




7. Quit Terminal, then confirm the symbolic link was created by returning to “~/Library/Application Support/MobileSync/” in the Finder, the “Backup” folder should now be a generic file with an arrow on it, signifying there is now a direct link between that “Backup” and the location specified on the external hard disk





8. Open iTunes and connect the iPhone, iPad, or iPod touch to the computer as usual, select the device within iTunes, select ‘This Computer’ as the backup location (optionally encrypting the backup), and then choose “Back Up Now” to start the device backup to the external drive





9. When the backup has completed in iTunes, double-check everything is in order by going to the folder on the external drive and confirming there is a “Backup” folder containing a hexadecimal named subdirectory – this is the backup made from iTunes of the device

That’s all there is to it. As long as the external hard drive is connected to the Mac, iTunes will now backup to that external storage volume rather than the internal hard disk. The backup will fail if the external hard drive is not connected to the Mac. Likewise, restoring an iOS device from a local backup will be impossible if the external hard drive is not connected to the Mac.

This offers a great way to save local disk space and offload iOS backups made in iTunes to another hard drive. You should still continue to backup to iCloud as well, since having dual backups offers a level of redundancy that is always appreciated should something go wrong.

If you’re interested in storing backups on external volumes, you may also be interested in moving an iTunes library to an external hard drive too, since that can further offload media and free up local disk space.

Creating External iTunes Backups Entirely with Command Line

Advanced users can also perform the entire process of directory creation, copying, and linking from the command line, if desired. The general syntax for that process would look like the following:

mkdir /Volumes/ExternalFileStorage/iTunesDeviceBackups/

cp ~/Library/Application Support/MobileSync/Backup/ Volumes/ExternalFileStorage/iTunesDeviceBackups/

cd ~/Library/Application Support/MobileSync/

rm -r Backup/

ln -s /Volumes/ExternalFileStorage/iTunesDeviceBackups/Backup/ ~/Library/Application Support/MobileSync/

Once the symbolic link has been created, open iTunes and start the backup as usual.

For what it’s worth, there are sloppy and less technical ways to go about this, mainly copying the iOS backup files from an internal drive to an external drive manually, then removing them from the internal drive, and copying them back from the external drive back to the internal drive when needed, but that’s really a hassle, and given how well the symbolic link process works, it’s just not necessary.