Switching to Apple’s Two-Factor Authentication
Apple has, for a while now, offered two separate additional security measures to protect your Macs, iOS devices, and iCloud account, but thanks to some inexpert nomenclature, it can be a little difficult to tell them apart.
The first, two-step verification, has been offered for several years. It prompts you to enter a four-digit code when you sign into your iCloud account, purchase something from one of Apple’s stores on a new device, or make changes to your Apple ID. Those codes were delivered by push notification to an authenticated device of your choosing, or via SMS text message.
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The newer two-factor authentication is an improvement upon that process, which Apple started rolling out last year. While the principle is similar, the execution is refined. The verification code is now six digits and is automatically sent to all of your authorized devices.
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Though Apple didn’t provide an obvious way to make that jump, the key is simply to deactivate your existing two-step authentication[…]
If you want to see a list of trusted devices and those that can receive two-factor codes (which largely but not entirely overlap), go to the iCloud preference pane on your Mac, or the iCloud section of Settings on your iOS device, and look at your account, then select Devices. That’ll provide a list of every device logged into your iCloud account; selecting each will tell you if they’re trusted and can receive two-factor codes.
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As mentioned in a subsequent update, two-factor authentication does not remove the need for app-specific passwords, but it does seem that you no longer need them for any Apple services.
I waited for two-factor authentication to arrive, never turning on the earlier two-step verification. When I turned on the newer technology, I changed my Apple ID password at the same time because the old password had been in use for a while. That was probably the main source of the problems that ensued.
It took two full days of responding to error alerts and other failures for the new Apple ID password to "take" and give me reasonable functionality. But it kept going bad from time to time on one machine or another for several days, forcing me to re-enter the new password again and again. In the process, I probably got more than 150 alerts on all my devices, telling me that my Apple ID had been added to FaceTime or Messages or whatever on a "new" iPad, a "new" iPhone, a "new" Mac Pro, or a "new" MacBook Pro. I was able to enter the two-factor authentication 6-digit code whenever I was asked for it, so at least that part of the process seemed to be working.
There have been many failures with the new Apple ID password, however, usually after hours or even a day of good functioning. A couple of days ago, for example, I had Messages syncing properly on my Mac Pro, MacBook Pro, iPad and iPhone. But the next morning it stopped syncing on my Mac Pro, and the Accounts pane in Messages Preferences was grayed out and refused to let me edit the information. Finally, after shutting down the Mac Pro and restarting, I was able to re-enter the new Apple ID password for the umpteenth time. The messages then started syncing again, but now the messages that were missed while it wasn't syncing won't sync.
Sometimes I had to try to enter the new Apple ID password 6 or 7 times in a row for one application or another, with alert after alert telling me it was invalid, until it finally was accepted. I'm a good typist and I was watching carefully, and I know I was entering it correctly at least 99% of the time. The application then worked well for a while, but a little later I would get more alerts telling me that it was invalid.
And the instructions about what has to be changed are incomplete. By accident, for example, I rediscovered that an Apple ID password is needed in AirPort Utility. Ever since changing the Apple ID password for iCloud and a number of other things, my home network had become very slow and remained slow for days. I know I have a bad cable into the house and I assumed that was the problem, but it had never been this slow before. When I entered the new Apple ID password in AirPort Utility, my network instantly became responsive again. But the next day, AirPort Utility was giving me an error message again to the effect that my Apple ID password is invalid, and I had to enter it yet again.
I'm really fed up with all these problems. Fortunately, all my devices seem to have been stable for more than 24 hours now. Knock on wood.