We transitioned to Office 365 4 months ago. Per this reference, we have left an Exchange Server 2010 on premise per this guidance.
I want to move Exchange 2010 to an older less capable server to repurpose the current server. I have installed it with client access and mailbox server roles.
When I try to uninstall the old Exchange 2010 installation, I can't do it citing the existence of mailboxes. When I attempt to remove an mailbox, the entire user is deleted from our Active Directory? Premise mailboxes are now irrelevant consider they exist on Office365.
How do I decommission this old Exchange 2010 server without deleting all our users?