How to get a list of all email addresses and aliases in Microsoft 365

Auditing all email addresses and aliases in your Microsoft 365 environment is a crucial task for maintaining organizational efficiency and ensuring proper email routing. Manually tracking all primary email addresses and their associated aliases is a cumbersome process, especially in larger organizations, and can lead to complex email delivery issues if not managed correctly.

This guide explores three methods to retrieve a comprehensive list of all Microsoft 365 email addresses and aliases using the Exchange admin center, PowerShell, and M365 Manager Plus.

Method 1: How to get a list of email addresses and aliases using the Exchange admin center

Prerequisites

The Exchange Administrator role is applied to the account you use to sign in to the Exchange admin center.

Steps

1. Log in to the Exchange admin center and navigate to Recipients > Mailboxes.
2. Click Choose columns, select Alias, and click Save.
3. Click Export Mailboxes to get a list of all email and aliases in Microsoft 365 in a CSV file.

Method 2: How to get a list of all email addresses and aliases using Exchange Online PowerShell (Get-Mailbox and Get-EXOMailbox)

Prerequisites

Before using Exchange Online PowerShell, please verify that:

1. The Exchange Administrator or Global Administrator role is applied to the account you use to sign in to Exchange Online PowerShell.
2. You are connected to the Exchange Online module.
   1. To check if the ExchangeOnlineManagement PowerShell module is installed, use this script:
      Copy Install-Module ExchangeOnlineManagement -Scope CurrentUser
Update-Module ExchangeOnlineManagement
   2. Connect to Exchange Online PowerShell with this script:
      Copy Connect-ExchangeOnline

Using Get-Mailbox to export the Microsoft 365 users email list

The Get-Mailbox cmdlet can be used to retrieve a list of all email addresses and aliases in Microsoft 365.

Get-Mailbox -RecipientTypeDetails UserMailbox -ResultSize Unlimited -Properties EmailAddresses | 
Select-Object DisplayName, PrimarySmtpAddress, @{Name="EmailAliases";Expression={$_.EmailAddresses | Where-Object {$_ -clike "smtp:*"} | ForEach-Object {$_ -replace "smtp:",""}}} | 
Export-Csv -Path "C:\Reports\AllEmailAddressesAndAliases-$(Get-Date -Format yyyyMMdd-HHmmss).csv" -NoTypeInformation -Encoding UTF8

Using Get-EXOMailbox to export a list of all email addresses and aliases

Microsoft recommends using the modern Get-EXOMailbox cmdlet to retrieve mailbox details. It is optimized for performance and will continue to be updated, whereas older cmdlets are maintained only for backward compatibility.

The following script will retrieve the display name, primary SMTP address, and all alias email addresses for every user mailbox and export the data to a CSV file.

Get-EXOMailbox -RecipientTypeDetails UserMailbox -ResultSize Unlimited -Properties EmailAddresses | 
Select-Object DisplayName, PrimarySmtpAddress, @{Name="EmailAliases";Expression={$_.EmailAddresses | Where-Object {$_ -clike "smtp:*"} | ForEach-Object {$_ -replace "smtp:",""}}} | 
Export-Csv -Path "C:\Reports\AllEmailAddressesAndAliases-$(Get-Date -Format yyyyMMdd-HHmmss).csv" -NoTypeInformation -Encoding UTF8

Supported parameters

Here are some of the key parameters that can be used with the Get-Mailbox and Get-EXOMailbox cmdlets for this purpose:

An example use case: Get a list of old email aliases in Microsoft 365

Scenario: An IT administrator is preparing to decommission a domain (old-domain.com) and needs to identify all users who still have an email alias with that domain.

This is the cmdlet the admin would have to run to generate a report of all users with an alias from the specified domain.

Get-EXOMailbox -ResultSize Unlimited -Properties DisplayName,EmailAddresses | 
Select-Object DisplayName, @{Name="MatchingAlias";Expression={($_.EmailAddresses | Where-Object {$_ -like "*@old-domain.com"}) -join ";"}} | 
Where-Object {$_.MatchingAlias -ne ""} | 
Export-Csv -Path "C:\Reports\OldDomainAliases.csv" -NoTypeInformation -Encoding UTF8

Method 3: How to view a list of all Microsoft 365 email aliases in M365 Manager Plus

1. Log in to M365 Manager Plus and click the Reports tab.
2. Navigate to Exchange Online > Mailbox Reports and click the Mailbox Users report.
3. This will list all Microsoft 365 user email addresses and aliases in your organization. You can filter for email addresses in specific domains using the Filter By field or export the list of Microsoft 365 email addresses and aliases in multiple file formats by clicking Export As.

Monitor your Exchange Online email addresses and more

M365 Manager Plus offers robust capabilities to manage and monitor email addresses and other critical aspects of your Microsoft 365 environment.

Important tips

Frequently asked questions