Glenn Fleishman, writing for Macworld [AUTOPLAY]:
If you’re using Apple’s two-step verification system for logins, I have just one (not two) questions for you: do you know where your Recovery Key is?
A friend recently went through a multi-week set of interlocked problems when he was locked out of his Apple ID account on his iPhone, and couldn’t find his Recovery Key. He wasn’t ultimately able to get Apple to unlock his account. (During this period, his phone also locked up for a few days and he couldn’t receive texts or alerts, either.)
He had forgotten he’d enabled two-step verification, which is the older of Apple’s two methods of using a second piece of information to validate that you’re the accountholder. With the two-step system, Apple uses something akin to Find My iPhone to provide a code on your iOS devices or sends an SMS that you use to complete your login.
If you are not sure what kind of verification you have in place on your account, read this post.
I used my two-step recovery key so often that I ended up memorizing it. But yeah, I wrote it on a Post-It and kept it in my home safe for security. I also stored it in SplashID, the password app that I use.
I strongly recommend upgrading to two-factor. Because only your trusted devices will display the unlock code. With the old two-step system, it’s still possible for someone to steal your recovery key if you’re not careful about keeping it secret.
(And Watch Auto Unlock on macOS Sierra won’t work unless you have enabled two-factor authentication.)
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