Office 365 – Find user by email address or alias

You can search for an Office 365 user by their primary email address or other aliases using Powershell.

First, connect to Office 365 with PowerShell

Once you are connected you can search for a specific address or export all addresses to a CSV file for analysis in another tool.

Find Office 365 User by Email Address

Example PowerShell code to find user by email address:

Get-Mailbox -Identity * |
Where-Object {$_.EmailAddresses -like 'SMTP:Testuser@tachytelic.net'} |
Format-List Identity, EmailAddresses

The above command will only find this specific email address and that will have to be the primary email address of the mailbox as denoted by the uppercase “SMTP”.

You can also do wildcard searches easily:

Get-Mailbox -Identity * |
Where-Object {$_.EmailAddresses -like '*paul*@tachytelic.net'} |
Format-List Identity, EmailAddresses

By default Get-Mailbox will only return results from active mailboxes. So you may need to specify the ” -IncludeInactiveMailbox” parameter.

Below is a form you can use to help you put together the command you need.

Email to find:

Include Deleted Users Do not Include Deleted Users

Required Powershell

Export all email addresses to a CSV File

If you prefer, you can simply output the email address of every user to a CSV file and analyse the addresses and aliases in another tool:

get-mailbox -identity *|
select-object Identity, EmailAddresses|
export-csv EmailAddresses.txt -NoTypeInformation