Volume 31 Issue 14

Issue Date: July 23, 2026 « Previous Issue | Next Issue »

The following articles were included in our Exchange Messaging Outlook (EMO) newsletter published on July 23, 2026.

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Today's Highlights »

Microsoft Account Aliases vs. Separate Accounts
Microsoft Is Requiring Passkeys and Removing SMS and Voice Options
Office on Mac or iOS not Working

Microsoft Account Aliases vs. Separate Accounts

I saw an interesting Reddit thread from someone who was confused about the difference between Microsoft account aliases and separate accounts.

The user opened the Microsoft account page for managing account names. At the bottom of that page, they saw the option to add an email address and then choose “Create a new email address and add it as a username.” They thought this would create a separate but linked Microsoft account, instead it adds a new alias to the existing account.

Can an alias become a separate Microsoft account? No. An address that is added to a Microsoft account as an alias cannot be moved to another account later. If you remove that address from the account, it is permanently retired and cannot be reused by anyone.

The same principle applies in reverse: separate Microsoft accounts cannot be merged into one account. (Oh how I’d like to merge some of my accounts.)

An alias is an alternate email address for the same mailbox. Messages sent to the alias arrive in your existing inbox, and replies are sent from the address the message was sent to.

You can make aliases easier to manage by using rules to Move messages sent to a specific alias into a dedicated folder. Or Apply a category so you can quickly identify which address received the message.

Aliases are useful for many of the same reasons people use multiple mailboxes: they help limit who has your main address and make spam easier to manage.
For example, you can use an alias when signing up on websites. If that address starts receiving too much spam, you can delete the alias or use a rule to move those messages to a folder.

If you only use aliases for website sign-ups, consider disabling sign-in for those addresses. Then, if a site database is compromised, the exposed address cannot be used to sign in to your Microsoft account.

Microsoft limits how many aliases you can create and keep on an account:

You can have up to 10 addresses on one Microsoft account.
You can create only one new alias every two weeks.
You can create no more than 10 aliases per year.

For example, if you add one alias per month for nine months and then delete one, you may need to wait until the oldest alias is a year old before you can add a replacement.

Aliases work well for incoming mail and replies. Replies are sent from the address that received the original message.

Sending a new message from an alias takes a little more attention. You need to choose the alias in the From field, and the display name is the same for all aliases on the account.

Changing the From address works in all Outlook apps. Many other mail apps send only from the primary address. If you have not disabled sign-in for the alias, you may be able to configure the account in another mail app using that alias and a different display name.

If you use Outlook on the web, you can change the default sending address for new messages by going to File > Settings > Mail > Forwarding and IMAP. This setting applies only to Outlook on the web. It does not change the default sending address in other Outlook apps.

If you want a different address to be the primary address for the account, make that change in your Microsoft account settings. Do not to remove an address unless you are certain you no longer need it. Removed Microsoft aliases cannot be recovered. Microsoft also limits primary alias changes to once every two weeks.

A second account can be useful when you need to send mail from a different address and want to keep that identity separate for privacy reasons. However, I would not use a second Microsoft account as the recovery account for the first one. Too many people end up locked out of both accounts, or they forget to use the second account, and it is eventually deleted.

If you do not sign in to an account regularly, Microsoft can purge the mailbox after one year and delete the account after two years. The exception is an account with an active Microsoft 365 subscription. In that case, mailbox purging and account deletion are paused while the subscription remains active. When the subscription ends, the inactivity clock starts again.

I prefer aliases over multiple accounts because they are easier to manage and help simplify email use. They also let me use different addresses when signing in to websites, which helps protect my main account from attackers.

If you truly need a second account, consider using a different email service, such as Gmail or Yahoo. For two-step verification and recovery, it’s best to use accounts from two different services. Just make sure you sign in to every email account at least once a year, so the account is not closed for inactivity.

Microsoft Is Requiring Passkeys and Removing SMS and Voice Options

Microsoft 365 business administrators received an email this week announcing that passkeys will become the default authentication method. Microsoft will retire SMS and phone-call delivery of 6-digit authentication codes on February 1, 2027.

Admins with users who currently receive codes by SMS or phone call should direct them to set up passkeys. Users who already have Microsoft Authenticator installed can continue using it, although Microsoft recommends passkeys (which are available in the Authenticator).

Passkeys are tied to a device or synced credential store and use cryptographic keys instead of shared secrets. They are resistant to phishing, SIM-swap, and replay attacks. Users already using phishing-resistant methods, such as Windows Hello or Microsoft Authenticator, can continue using them.

Microsoft Entra ID supports passkeys saved to a platform credential manager (such as iCloud Keychain, or Google Password Manager) and synced across the user's devices. They also support device passkeys, where the passkey is created and stored on the user’s device. This includes FIDO2 hardware security keys. And passkeys in Microsoft Authenticator.

My recommendation: if your browser or password manager offers to save a passkey, accept it. Passkeys are more secure and easier than entering a password and then approving the sign-in in an authenticator app. (I use LastPass, and it began prompting me to save passkeys a few weeks ago, even though my accounts are also set up in Microsoft Authenticator.)

This change applies to business accounts, but Microsoft also encourages consumer account users to use passkeys. I don’t have information indicating that SMS will be disabled for consumer accounts, but the number of users who struggle to receive SMS codes is not a good sign. Voice authentication for consumer accounts was turned off several years ago.

For more information, admins can visit Passkeys by default and retirement of Microsoft-provided SMS and voice authentication - Microsoft Entra ID | Microsoft Learn

Office on Mac or iOS not Working

Beginning July 13, 2026, some Mac users found that their Office apps - Word, Excel, PowerPoint, Outlook, or OneNote - could open and print files but could not edit, save, or create them. This is called “reduced functionality mode,” which occurs when Microsoft Office apps are used on older operating systems or devices that are no longer supported. For macOS and iOS, Office is only supported on the last three versions.

If your device can upgrade to the latest macOS or iOS, installing the update should resolve the issue. If it cannot support newer operating system versions, you can still use the web versions of the apps.
If you have Office 2019 and are already running the latest macOS, consider upgrading to a Microsoft 365 subscription.

For more information, see Update Microsoft 365 or Office on your macOS or iOS device