iPhone Backup Trick

Problem

What do you do when you run out of disk space on your Mac and can't backup your iPhone?

Solution

Create a symbolic link for your iTunes backup folder, linking it to an external hard drive.

Details 

There are two ways to backup your iPhone. You can back it up to either iCloud or iTunes. iCloud is convenient because it happens automatically (daily) when the phone is charging and on a WiFi network. But, the downside of an iCloud backup is that the restoring process can take days – many days – depending on your bandwidth. Even if you have a blazing fast Internet connection, the bottleneck will be with iCloud's servers since your personal data isn't cached on a CDN.

I typically keep my iPhone set to backup to iCloud until I buy a new iPhone. With a new iPhone, I'll connect it to iTunes and choose to make an encrypted backup to my hard drive and then I'll restore the backup to the new iPhone. (Choosing the encrypted iPhone backup option will save your passwords, and other sensitive data, thereby saving time when you restore from your backup.)

But, since my iPhone 7 has 256 GB of storage, I quickly discovered that I didn't have that much free space on my MacBook Air. What to do? I tried freeing up some space, but that wasn't enough.

Then I remembered that I had a 2 TB external hard drive with enough free space. So, I dropped to the command line and created a symbolic link to the external drive. To accomplish this, go to Terminal and cd to:

/Users/username/Library/Application Support/MobileSync

I temporarily renamed the Backup folder, under MobileSync, to Original Backup. Then I created the UNIX symbolic link, with the name Backup, to a Backup folder on the external drive:

ln -s /Volumes/MyExternalDrive/Backup 

Once I created the link to the external drive, I changed my backup option, in iTunes, to "This computer" and clicked the Back Up Now button. It took a few hours, but that was better than a few days. After the backup completed, I connected my new iPhone X to iTunes and restored the back up (which took about two more hours), then deleted the symbolic link, and changed the Original Backup folder name to Backup.

Initial Setup

Old iPhone 7 shaking hands with my new iPhone X

Finally, my favorite part of the iPhone X is, to initially set it up, I simply placed my old iPhone 7 next to my new iPhone X. The iPhone X sensed the older iPhone 7, asked for my PIN, and viola, it began transferring the initial setup information.

Gestures

Need help learning the new iPhone X gestures?
This 5' 30" video will get you primed up.

Face ID

Face ID seems to be working as expected. Frequently, in the time it takes for me to pick up my iPhone X and adjust my grip, it's unlocked.

With Apple's Face ID on iPhone X, the odds of a false positive is down to 1 in a million. That loosely means there are 7,500 people in the world who can unlock my iPhone X – that's a huge improvement over Touch ID which theoretically gave 1.5 million people the ability to unlock my iPhone with their fingerprint.