Those affected by the problems say that engineers are aware of what's going on, so you might be in the clear by the time you read this. We've reached out to Apple for more details, and we'll let you know if it has more to add. One thing's for sure: this is a not-so-friendly reminder of the risks of trying pre-release operating systems with accounts and devices you can't afford to lose.

[Thanks, Kristy]

Update: Some users report that you can use a link in your two-factor authentication email notice to disable the security measure and thus recover your account. You'll still have to wait until the underlying issues are resolved to turn two-factor back on, but it beats a total lockout. Thanks, Hemmik!