Exchange 2016 Hybrid Mailbox Conversion

[Checior200]

Hello,

We have Exchange 2016 in a hybrid environment. We have user with converted mailbox (sharedmailbox) - after some time when user back to org, we had to convert it one more time to UserRemoteMailbox. 

I used command Set-RemoteMailbox -Identity %UserName% -Regular and in the EAC i see that Mailbox is converted to userMailbox. But after delta synchro in o365 exchange admin center shows SharedMailbox. 

What can I do in this case? 

[#2]

Hi @Checior200,

To convert a shared mailbox to a user remote mailbox in a hybrid Exchange 2016 environment, you need to perform the following steps:

1. Make sure that the user account in Active Directory has the correct permissions. The user account must be a member of the Mail-Enabled Users group and the Mailbox Users group.
   
   
2. Make sure that the user's mailbox is not archived. If the user's mailbox is archived, you need to restore the mailbox from the archive before converting it to a user remote mailbox.
   
   
3. Make sure that the user's mailbox is not in litigation hold. If the user's mailbox is in litigation hold, you need to remove the litigation hold before converting it to a user remote mailbox.
   
   
4. In the Exchange Management Shell on the on-premises Exchange server, run the following command:

Set-RemoteMailbox -Identity <UserMailboxIdentity> -Type UserRemoteMailbox 

1. Force a synchronization between the on-premises Exchange server and Exchange Online. To do this, you can use the following command:

Start-ADSyncSyncCycle -PolicyType Initial

1. In the Exchange Online Admin Center, verify that the mailbox type has been converted to user remote mailbox.

Useful links you can use:

• Convert a shared mailbox to a user mailbox: https://learn.microsoft.com/en-us/microsoft-365/admin/email/convert-user-mailbox-to-shared-mailbox?v...
• Troubleshooting shared mailbox conversion issues: https://learn.microsoft.com/en-us/exchange/troubleshoot/user-and-shared-mailboxes/shared-mailboxes-unexpectedly-converted-to-user-mailboxes

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Kindest regards,

Leon Pavesic
(LinkedIn)