I was setting up some testing in my labs recently and synced a user from AD to O365. I noticed this user had the primary email address of the onmicrosoft domain which I didn’t want.
When I tried to change this in Exchange online I was presented with an error:
Now I don’t have exchange configured on premise as a hybrid, which is where I would immediately go so I turned to PowerShell but got quite a similar error in there too.
I then came across this: https://support.microsoft.com/en-us/kb/2492140 – ah! So I headed into ADUC, onto my user, Attributes tab, found ProxyAddresses and added what I wanted.
A couple of notes:
- If you don’t see the Attributes tab make sure you have Advanced Features ticked under the View menu of ADUC
- If you prefix your address with SMTP it will become primary, if not it will be set as an alias
- You can add as many alias’ as you wish
Here’s what mine looked like:
After a DirSync/Azure AD Sync ran my primary SMTP address updated and my extra email address was also added.
Hope it helps!