macOS Contacts USB Sync Confirmed Broken in macOS 10.13 High Sierra

After weeks of collaboration with AppleCare Support, we finally received a call from AppleCare today confirming our suspicions – since macOS 10.13 High Sierra, something has fundamentally broken in the way iTunes performs USB syncing of Contact records.

In a nutshell, the bad news is, yes.

Its completely broken.

For those of us who rely on USB syncing as the last bastion of privacy and some form of control over our personal data, please take note of this article. This is for you.

You are strongly recommended to do a physical comparison between the Contacts records and their details within your iOS devices against your macOS device that you USB sync with.

Ever since macOS 10.13 High Sierra all the way till its current iteration at press time, macOS 10.13.4 USB sync has been broken.

“Broken” means that no error is displayed during or after the USB syncing indicating anything is wrong. For all intents and purposes the USB sync appears to have completed ‘successfully’.

A quick comparison between the iOS and macOS Contacts app records, will reveal that no update had been performed in either direction, i.e. no new changes made on iOS Contacts are updated to the macOS Contacts app and vice-versa.

The easiest way to determine this is to scroll to the bottom of your Contacts listing on your iOS and macOS devices. If you have been USB syncing regularly, you should see a mismatch in the total number of Contact records between iOS and macOS devices, e.g. 100 records on iOS vs 90 records on macOS.

This discovery was made with iTunes 12.7 and its later iterations up until the latest at press time, 12.7.4.76.

Don’t even begin to attempt to install an earlier version of iTunes. We have already been there and done that. It won’t work either.

Although Apple Inc hasn’t officially relayed the details as to what is broken and where, based on our testing it definitely has something to do with the core of macOS 10.13 High Sierra and less to do with iTunes.

If you would like to test the authencity of this discovery, you can do the following:

1. install a fresh macOS 10.13 on a mac
2. restore an iPad or iPhone to factory settings
3. turn off iCloud Contacts syncing on your iOS and macOS devices
4. launch Contacts in macOS and create a new Contact record
5. launch iTunes and enable Contacts USB syncing
6. Perform a USB sync between the macOS and iOS devices

Repeat the above process a couple of times from step 4 onwards.

You can even alternate between creating the next new Contact record  on your iOS device instead of your macOS device or vice-versa and generally, you will find that the USB Contacts sync will continue to work all the way up to about the seventh (7) Contacts record you create.

After the seventh record, the USB Contacts sync completely fails and refuses to function permanently.

Why the seventh record you ask? Frankly we do not know and Apple Inc has not provided any details.

For those of you who have been relying on USB sync to keep a backup of your iOS Contacts records on you macOS device and vice-versa, please take note because the USB sync has not been working, your Contacts apps most likely do not match and if you lose your iOS device now, your macOS device may not contain the latest version of your iOS Contacts records. Ergo, your latest iOS Contacts records will be lost together with your iOS device.

One immediate ‘remedy’ you may want to consider is, begrudgingly turning on your iCloud Contacts sync for the first time.

Otherwise, Apple Inc, for the time being has not offered any official stop-gap remedy other than to wait for their next Software Update.

Please note the following is not recommended for novice users and you are strongly advised to perform a backup of your systems before attempting anything as this process results in irreversible destructive consquences to your macOS Contacts app records.

If you do not feel comfortable with performing this, its probably best that you don’t and wait on Apple’s next Software update or turn on your iCloud Contacts syncing (which opens another cans of worms frankly) if you cannot wait.

For us here at MacRiot, what we have resorted to following for the time being. What follows is a way to at least force a one-way USB Contacts sync from our iOS device to our macOS:

1. ensure that your Contacts or iTunes app is not running on your macOS device
2. in Finder click “Go” and select “Go to Folder…”
3. copy and paste the following filepath into the text field “~library/Application Support/Addressbook/”
4. in the Addressbook folder select all the files and folders and delete them
5. launch iTunes and perform your USB sync as you normally would with USB Contacts sync enabled

The above process will delete all existing Contact records and groups from your macOS Contacts app and the first time you USB sync your iOS device will result in the update of all Contact records from your iOS device to your macOS Contacts app.

This only works once.

If you want to refresh your macOS Contacts app again, you will have to repeat the above procedure.

This means that we ONLY use our iOS device to enter new information into our Contacts app and treat it as the singular point to create, edit and remove Contacts.

We do not create, edit or remove Contacts on our macOS Contacts app as the USB sync has no way of functioning from macOS to iOS using the above method.

Once again, use at your own risk. This is not an Apple approved or sanctioned method.

In the mean time, you are encouraged to forward your challenges to Apple to create greater awareness that it is not only a small pool of people who are affected by this outage. Then maybe we will see a fix sooner rather than later.

[Update, 01 May 2019: finally. Its appears that the rest of the Mac community has started picking up on this bug that has been unofficially confirmed by Apple, some citing that the USB sync breaks when custom values for Related Contacts, eg "son" and "daughter" are used in Contact records. Its definitely a bug that Apple needs to fix but the question is when? You can help by sending more feedback to Apple as well as adding noise across the Internet to raise the focus to this issue. Read more here]