As some of you probably know, when synchronizing objects from the on-premises Active Directory to the Office 365 tenant, the on-premises Active Directory is considered the source of authority meaning that the objects must be managed via the on-premises Active Directory.
In this scenario you can of course change the primary e-mail address a PowerShell script or maybe even the provisioning solution running in the particular on-premises environment. However, there are organizations that aren't, how should I put it, very PowerShell savvy.
Well, there are good news for you folks! Because, here I want to show you how this can be accomplished using a GUI-based tool called ADModify. Those of you with many years in the IT business probably know this tool from the good old pre-Exchange 2007 days, where we didn't have an Exchange product that supported PowerShell. If not, check this article, I wrote back in 2005: http://ow.ly/lqdi8. Yes thats a lot of years ago, but actually the tool haven't changed much since then.
The domain you wish to set as the primary e-mail address for your users must have been:
- Added as an "Accepted Domain" in your on-premises organization (if running in Exchange hybrid mode)
- Added as a verified domain in your Office 365 tenant
Now go download the ADModify tool here: http://ow.ly/lqdnX.
Launch the tool and select the users for which you wish to change the primary e-mail address by following the instructions in the old article, I wrote: http://ow.ly/lqdi8
Click the "E-Mail Addresses" tab and tick "Add SMTP Address". Now enter the format of the first part of the e-mail address (default is "mailNickName") and type the domain after the "@" sign. Also make sure you tick "Set as Primary" and "Update E-mail Address on the General Tab".
Now click on the "Go!" button to make the changes. This can take several minutes depending on how many objects you're modifying.
When done, you need to perform a manual sync with the AAD sync tool or wait for the next scheduled synchronization (occurs every 3 hours).
The primary e-mail address have now been changed for the in this case remote user mailboxes that were selected in ADModify.