Office 365: Change Primary email address of Active Directory user

It is simple to change the Primary Email Address of an Office 365 user when your tenant is not being synced to your on-premises active directory, but if you are syncing to Office 365 with any of the following tools:

• Windows Azure Active Directory Sync (DirSync)
• Azure AD Sync (AADSync)
• Azure Active Directory Connect

Then you will be unable to change any of email addresses associated with that account, and you will get the following error:

The operation on mailbox “Mailbox” failed because it’s out of the current user’s write scope. The action ‘Set-Mailbox’, ‘EmailAddresses’, can’t be performed on the object ‘Mailbox’ because the object is being synchronized from your on-premises organization. This action should be performed on the object in your on-premises organization.

How to change the Primary Email Address for an Office 365 account using Active Directory Users and Computers

1. Open Active Directory Users and Computers
2. Ensure you have “Advanced Features” enabled from the view menu:
   
3. Double click on the user that you want to edit the email addresses for.
4. Go to the “Attribute Editor” tab.
5. Go to the “proxyAddresses” attribute and click edit.
6. Edit the email addresses as per your requirements. Note that the primary address (which is the address that the user will send emails from) is in uppercase “SMTP”.
   

How to change the Primary Email Address for an Office 365 account using Powershell

You can perform the same operation using Windows Powershell, the basic syntax is like this:

Set-ADUser paulie -Add @{ProxyAddresses="SMTP:[email protected]"}

The problem with running this command is that you may already have a primary SMTP address set and this will not stop you from adding another one. So first of all run:

get-aduser paulie -properties proxyaddresses | Select-Object Name,ProxyAddresses |fl

This will show you all the current proxy addresses for this user. If you want to remove an existing proxy address you can use:

Set-ADUser paulie -Remove @{ProxyAddresses="smtp:[email protected]"}

It is possible neither of the above methods will work if you have never had Exchange installed locally, as the users will not have these attributes. You can follow the instructions on this page in order to get the attributes enabled for your users.

If you have any questions, feel free to ask in the comments.