Transfer mailbox to an existing user

Adrian Van de Voorde 0 Reputation points
2023-04-24T15:41:10.7+00:00

Hi All, So I'm in a confusing situation here. In the past we were using CompanyX as a domain name, so address was USER@companyX.com. This was back when everything was still on prem. Today we've cut our Exchange server and everything is on the cloud. So right now we're having user@companyX.com which is a prem-synced AD-account with it's mailbox in the cloud.

Company structure changed over the years and the company split to company X & Y, next to each other. there was no use for a second AD user, so some colleagues created for this same person USER@companyY.com this is entirely created in the cloud. So we're having a new entity for the same user, totally seperate.

CompanyX is less and less used so the user, who is quite important in the company so can ask for whatever he wants, Would like to have all the content from his CompanyX account archived (which is not the pickle here) and keep on working with the companyY structure in his mailbox, connected to his regular (AD) user. Is it possible to:

  1. detach this user's mailbox, user@companyX.com, without ruining the AD account?
  2. disconnect the user@companyY.com from the cloud-user and connect it to the prem-synced account? Thanks for your time!
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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 Exchange Hybrid Management
Microsoft Exchange: Microsoft messaging and collaboration software.Hybrid Management: Organizing, handling, directing or controlling hybrid deployments.
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  1. Jarvis Sun-MSFT 10,176 Reputation points Microsoft Vendor
    2023-04-25T09:42:57.6833333+00:00

    Hi @Adrian Van de Voorde

      “Would like to have all the content from his CompanyX account archived (which is not the pickle here) and keep on working with the companyY structure in his mailbox, connected to his regular (AD) user”  

    Please clarify whether companyX and conpanyY are under the same tenant?

    If yes, for the part of the X mailbox, you can first export the content to PST, and then remove the license of X. Then use SMTP matching to associate Y's mailbox with X's AD account.

    More detailed steps please refer to: How to use SMTP matching to match on-premises user accounts to Office 365 user accounts for directory synchronization - Microsoft Support


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