iOS 16.3 has added a two-factor authentication requirement for iCloud Backup and iCloud Drive to make your device backups and files in the cloud more secure.
- What’s happening? Using iCloud Backup and iCloud Drive no longer works for Apple ID accounts without two-factor authentication after updating to iOS 16.3.
- Why care? Affected users have two-factor authentication turned off for their Apple ID. By adding a two-factor authentication requirement for iCloud and Drive, Apple is making your device backups and cloud files more secure.
- What to do? Turn on two-factor authentication for your Apple ID.
iCloud Backup and Drive now require two-factor authentication
Two-factor authentication (2FA) adds another layer of security to your Apple ID by requiring your username, password and a unique one-time code when logging in on a new device. Over the years, Apple has been adding more and more services to the list of iCloud features that require that 2FA be turned on.
For example, you couldn’t use Apple Pay or the Sign in with Apple feature or sync Messages and Keychain passwords across devices unless 2FA was enabled.
As of iOS 16.3, iPadOS 16.3, tvOS 16.3, watchOS 9.3 and macOS Ventura 13.2, two new Apple services now require 2FA, iCloud Backup and iCloud Drive.
If you don’t have 2FA turned on for your Apple ID account, and you update your iPhone to iOS 16.3, you’ll be greeted with an error message when trying to back up your phone to iCloud or have apps sync their content via iCloud Drive.
“An Unknown Error Occurred”
The update disables syncing with iCloud Backup and Drive for any users that don’t have 2FA enabled, telling an unsuspecting user that “An Unknown Error Occurred.”
The cryptic message doesn’t provide an explanation for what went wrong, leaving users in the dark. Attempting to turn on iCloud Backup and Drive in Settings → [your_name] → iCloud without enabling 2FA produces an error message.
For the sake of completeness, we should point out that some people also complained via Apple Support Communities about iCloud Photos being turned off and not turning on again.
As iPhoneTricks suggests, this problem seems to be related to Apple’s new Advanced Data Protection for iCloud feature that’s available globally with iOS 16.3 after launching in the United States alongside iOS 16.2 in December 2022.
What is Advanced Data Protection for iCloud?
Advanced Data Protection turns on end-to-end encryption for almost all iCloud services, including Backup. With it enabled, encryption keys for accessing your data are transferred to your device and deleted from Apple’s servers. As a result, no one but you can access your iCloud data. Also, when Advanced Data Protection is used, Apple cannot fulfill government requests for iCloud backups.
You can turn Advanced Data Protection for iCloud on and off in Settings → Apple ID → iCloud → Advanced Data Protection. For further information, read a support document on Apple’s website.
iOS 16.3 also adds support for hardware security keys such as YubiKey. If you have one of these, you can use a physical security key (NFC or Lightning-based) as an alternative to two-factor authentication. So, this feature requires a physical security key instead of one-time codes.
You can turn on the Security Keys for Apple ID feature and add your physical security keys via Settings → Apple ID → Password & Security → Add Security Keys. Additional information is available in Apple’s support document.