Office 365 alias to email

New Contributor

I want to change an existing alias to a regular email account.  Once I delete the Alias and then create the user, how long does it take for the email that was going to the alias to go to the newly created mailbox?  During this transition, will any mail be lost if it is sent while making this change?

3 Replies



If you are synchronising AD to O365 with Azure AD connect, then you will need to remove the alias on-premise and then either wait for AD sync to run, or force a sync manually. If cloud only, it's a lot quicker and simpler.


Even taking AD sync into account, the process can be done very quickly.  Assuming you have directory sync in place, I'd suggest;


1). Remove the alias from the on-prem object

2). Run manual sync of AD connect from the AADC server by going to PowerShell and running Start-AdSyncSyncCycle -PolicyType delta

3). Check that the alias is removed from the O365 account

4). Create new remote mailbox on-prem and then re-run the manual sync from step 2 again.


You should not see any emails bouncing during this time if you carry out these steps swiftly enough.


If you are cloud only, the process will be even quicker and easier as you can do all of the steps from the Office 365 Admin Center.

Since I'm cloud only, I don't have to worry about step 2?  Just delete the alias, double check that it's gone, then create the user?

best response confirmed by johnbentrim (New Contributor)
Yes, nice and simple. You are good to go.