The GuruXP Blog

On todays post I’ll explain how to remove a domain name from an office365 subscription, either because you’re migrating to anoyher family plan, your trial subscription is about to end, or just because we’re not using the domain name anymore.

The first thing we must do is set the users that are using the domain name to use another domain name (the .onmicrosoft.com domain for example). This implies two things to check out: the login UPN suffix (whats on after the @ symbol), and the proxy addresses (also called aliases) assigned on each users email addresses tab inside their properties.

So how do we do it via GUI (Graphical User Interface)?:

• Access our Office365 portal with Admin credentials.
• Go to Users and Groups.
• Select all the users we’re about to change and click on edit.
• Go to Details, and on Domain select another one.

For proxy addresses, we’ll have to do it one by one editing the details and clicking on the more tab and then on edit exchange properties, go to the email addresses section and delete the ones with domain name that we’re willing to remove.

So how to do it via PowerShell?:

• First of all, we need to get our environment ready for the use of PowerShell with Office365.
• Then we need to connect to our Office365 subscription with the following cmdlets:

$LIveCred = Get-Credential $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://ps.outlook.com/powershell/ -Credential $LIveCred -Authentication Basic -AllowRedirection Import-PSSession $Session

• Run the following to get the users that have the domain name we want to remove assigned:

Get-MsolUser -DomainName [Domain] | fl UserPrincipalName

• Change the desired users with the following:

Set-MsolUserPrincipalName -UserPrincipalName [CurrentUPN] -NewUserPrincipalName [NewUPN]

Once we’ve deleted the domain name from the users, we must do the same with distribution/security groups. To do so, we must access the Exchange Online Control Panel (if you have a small business plan, you must follow this article to access the ECP), clicking on the upper right side where it says «Admin» and then on «Exchange«, go to «groups» and edit each one of them under the «email addresses» section and delete the one containing the domain name we want to remove.

The same thing happens with shared mailboxes, site mailboxes and Lync Online users.

When we get done and checked out every single user containing the domain name to be deleted, we must click on the company name on the main screen of the Office365 portal and change the associated domain.

So, we’ve checked out users, distribution/security groups, shared mailboxes, site mailboxes, Lync Online users and the associated domain, now it’s the time when we can proceed to its deletion accessing the domains section inside the office365 portal, you just need to select the domain and delete it.

If we want to do this via PowerShell, this is what we need to run:

Remove-MsolDomain -Domain dominio.com