Uninstalling Exchange servers after migrating all mailboxes to Exchange Online

MamadouCoulibali-4946 571 Reputation points
2024-03-26T14:30:52.0233333+00:00

Hello community,

I have recently migrated all of our mailboxes to Exchange Online. I am wondering if it is safe to uninstall all of our on-premise Exchange servers without causing any issues. Would someone be able to provide me with guidance on the proper steps to take and any potential risks involved?

Thank you.

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Exchange Online
A Microsoft email and calendaring hosted service.
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Windows for business | Windows Client for IT Pros | Directory services | Active Directory
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  1. Thameur-BOURBITA 36,266 Reputation points Moderator
    2024-03-26T14:36:49.12+00:00

    Hi @MamadouCoulibali-4946

    If you still have a hybrid environment and synced users from active directory , you have to keep at least one Exchange server to be able to edit Exchange attributes from active directory.

    Synced objects cannot be modified from Entra ID.

    For more information please refer to :

    Why you may not want to decommission Exchange servers from on-premises


    Please don't forget to accept helpful answer

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  1. JayceYang 1,571 Reputation points Moderator
    2024-03-27T02:18:20.6133333+00:00

    How did you migrate the mailboxes to Exchange Online? Hybrid migration?

    If yes, you also need to confirm whether you need directory synchronization or password synchronization or ADFS.

    There may be 3 scenarios:

    1. Currently, if you keep an Exchange server running just for recipient management, you may be able to shut down your last Exchange server and manage recipients using Windows PowerShell. For more information, see Manage recipients in Exchange Hybrid environments using Management tools.
    2. All of the users will be managed in Microsoft 365 or Office 365, and there are no other directory synchronization requirements, you can safely disable directory synchronization and remove Exchange from the on-premises environment.
    3. The customer is planning on keeping AD FS, they'll also have to keep directory synchronization since it's a prerequisite. Because of that, they can't fully remove the Exchange servers from the on-premises environment. However, they can decommission most of the Exchange servers, but leave a couple of servers behind for user management. Keep in mind that the servers that are left running can be run on virtual machines since the workload is shifted to Exchange Online.

    All the steps for these scenarios you could refer to the following official document:

    How and when to decommission your on-premises Exchange servers in a hybrid deployment | Microsoft Learn

     


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