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Regular Visitor

Hi, looking to understand more about the domain in O365 tenants, which I've seen some info here. We are looking to cleanup users in our tenant that was created quite some time ago.  We have hundreds of users with the instead of our company's domain that we've since added.  How have others done this cleanup?  Do you mass delete all users with the emails?  Is it correct to assume that all the accounts were added prior to us adding our company's domain?  What happens when you swith the default from to your companys primary domain?

9 Replies
best response confirmed by Jeff Medford (Community Manager)
The users were either created before you synced your domain or created manually in O365. You can switch their UPN to be your corporate domain instead of and users should then be able to login with their corporate credentials (assuming you are doing some form of AD Connect or Sync). The one limitation as far as I know is that after switching the UPN suffix their profile properties won't sync fully since the pre-existing properties will be preserved. At least that is what I've seen in practice.
a lot of companys start with accounts and after they add the domain they change it. you should check if you did not add aliasses to the accounts before deleteing. In another case they use the accounts for admin accounts so it is clear who is a admin. kr, Paul

my current client is using accounts for administrative purposes. Their admins use their domain accounts for day-to-day activities and when they need to do admin tasks, they open an in-private session to login with their account.

You can change these accounts to your public routable UPN which is normally the users email address. If you run the following command to change this using PowerShell Set-MsolUserPrincipalName -UserPrincipalName -NewUserPrincipalName or if you want to change lots of users you can import from a CSV file the list of addresses you want changed and changed to import-csv c:\temp\names.csv | foreach{Set-MsolUserPrincipalName -UserPrincipalName $_.Users -NewUserPrincipalName $_.Email }

@Erin Scupham   what am I doing?  All I am attempting to do is get things set up properly for O365

need help with getting o365 set up properly

@Erin Scupham