Decommision on-prem Exchange 2010 with Azure AD Sync while using EXO (no Hybrid)

Marcel K 21 Reputation points

Hello there,

the customer situation right now is like:

  • Migration from on-prem Exchange2010 (SB2011) to EXO already completed before a few month (included connectors, mail flow in and out public folders and all stuff)
  • Azure AD Sync is running and all mailbox users in the cloud are synchronized from the on-prem AD
  • SBS2011 is running on a Windows Server 2008 (DC) and there the hybrid-migration just didnt work (even with MS Support)

as it should be after:

I just wanna decommision the on-prem EXC2010 without losing any of the synchronized mailboxes / AD User in the cloud, so I finally can remove the sbs2011 and complete the new DC server (Windows 2019).

SBS2011 would be just shutdown if there is another DC in the network at the same time.

Think that I have to set the azure sync off while I delete the databank, address books, mailboxes in the on-prem exchange before the deinstallation?

Anyone here already did something like that before and can give some tipps or introductions?

Thanks in advance!

Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
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Microsoft Entra ID
A Microsoft Entra identity service that provides identity management and access control capabilities. Replaces Azure Active Directory.
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Accepted answer
  1. KyleXu-MSFT 26,211 Reputation points

    @Marcel K

    To narrow down this one, I would confirm those information with you:

    • How mailbox migrated to Exchange online?
    • Are AAD Connect created before or after migration?
    • Do you mean you want to migrate mailboxes with hybrid but failed to create hybrid?

    Those information could help us know the status of your Exchange online mailboxes.

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  1. Marcel K 21 Reputation points

    Its done, no problems after the process as well.
    Thread can be closed now, ty