To use Apple’s two-factor authentication (2FA) with your Apple ID account — something the company has effectively mandated for the past few years — you must have at least one “trusted phone number” associated with your account. . A trusted phone number can receive a code via SMS or an automated voice call speaking the code to validate a connection on a new device. This contrasts with a trusted device, which is any iPhone, iPad, or Mac signed into that Apple ID account.
You can add multiple trusted phone numbers, which is useful for backup in case a phone is lost or a phone number is hacked. But you must have at least one.
Some readers find that they can’t set up their Apple ID for 2FA with a number already associated with another Apple ID account, or they can’t add such a number as a second trusted phone number or ulterior. They receive an alert that the number is already in use by another Apple ID account. This is especially irritating to many people who rely on verifying their Apple ID login using a trusted device and never trust the trusted phone number.
Apple has not documented this limitation. To me this felt like a change, but I can find people posting about receiving an alert like this from a few years ago. I just tested adding to my list of trusted phone numbers a family member’s cell (with their permission) already assigned to their Apple ID. I had no alerts or difficulties.
One reader found this particularly vexing: he had an old Apple ID account that he no longer used, but because his current, unique phone number was associated with that account, he was unable to complete setting up a new account. They were looking to delete the old account by calling Apple Support; I wouldn’t try to just delete it, because it’s unclear if deleting the account will really free up the old number.
Other posters on the internet discovered that they had been told the number was already used with an Apple ID, but not by them. They had new phone numbers which the previous owner had clearly connected to an Apple ID account and never disconnected or deleted.
Beyond going to support.apple.com to set up a support call with Apple to try to resolve the situation, you can simply acquire another phone number. Google still lets you create a Google Voice account at no cost and assigns it a legitimate phone number. You can then add this phone number as a trusted number. You can set up your Google Voice number to forward text messages to email or access the account directly through a web browser or iOS app.
This Mac 911 article is in response to a question submitted by igamesnews reader Zane.
Ask for Mac 911
We’ve compiled a list of our most frequently asked questions, along with answers and column links: read our awesome FAQ to see if your question is covered. Otherwise, we are always looking for new problems to solve! Email yours to [email protected], including screenshots if available and if you want your full name used. Not all questions will be answered, we don’t respond to emails, and we can’t provide direct troubleshooting advice.
