Change default domain

[Alisa Buck]

We have set our corporate domain as the default domain and are syncing it with AD.  We need to change the default domain back to the onmicrosoft domain but leave the users on the corporate domain so that we can federate our corporate domain.  Can we do this without breaking user login/credentials?  What other impacts are there that we might need to be aware of?

[#2]

Hi Alisa,

When you change the login name (UPN) it will break the login of the users to the new one.

What are the whole scenario ? Can you describe more ?

[#3]

We built our tenant and changed the default domain from the onmicrosoft domain to our corporate domain.  We then added our users and set AD to sync to the corporate domain.  We now want to federate the corporate domain.  However, it is now the default and so can't be federated.  We have been told to change the default domain from the corporate domain back to the onmicrosoft domain and then we can federate the corporate domain.  We are questioning what impact that will have on our users before we take that action.

[#4]

What you are federating, please describe more

[#5]

I'm not sure what you are asking.  We want to federate our corporate domain so that we can move to SSO.

[#6]

Hi Alisa,

You do not need to change the UPN to onmicrosoft to implement ADFS, just setup.

Please follow this link https://blogs.technet.microsoft.com/rmilne/2017/04/28/how-to-install-ad-fs-2016-for-office-365/