unable to migrate

Question

Hi All,

I am using an Exchange 2016 hybrid environment and facing an issue migrating a user from on-premises to online. I am seeing the error below.

I tried using the Enable-RemoteMailbox syntax from on-premises, but it did not work since the mailbox already exists in the on-premises environment.

Enable-RemoteMailbox -id "user1" -RemoteRoutingAddress "user1@contoso.mail.onmicrosoft.com" -alias user1
This task does not support recipients of this type. The specified recipient User1 is of type UserMailbox. Please make sure that this recipient
matches the required recipient type for this task.

If I delete the mailbox from the on-premises Exchange and execute the Enable-RemoteMailbox command, will it work?

Please note: I do not want the Active Directory account to be deleted, as I cannot recreate the account in AD. In our environment, AD accounts are created by an IAM tool.

Could someone guide me on how to delete the mailbox in on-premises Exchange without deleting the associated AD account or guide me how to troubleshoot migration error.

Answer 1

Hi, @Glenn Maxwell

Based on your description, if you delete the mailbox from your on-premises Exchange and then execute the Enable-RemoteMailbox command, it should work fine. This is because the user will no longer own the local mailbox, and the cmdlet can create a remote mailbox for the user in a cloud-based service, and if they do, the data in the local mailbox will be lost.

Considering that you can't delete an Active Directory account, you can try disabling the mailbox. When you disable a mailbox, all Exchange attributes are removed from the associated user account in Active Directory. Disable or delete a mailbox in Exchange Server | Microsoft Learn

The GUI operations for Exchange 2016 are visible: Step by Step How to Delete Mailbox Without Deleting User Account in Exchange Server : MKS Technology Inc

For errors during migration, you can try the following common suggestions:

1.The issue does not affect the entire database, but a specific mailbox. You can refer to: How to Fix Error “Too Many Transient Failure Retries Permanent Exception”?

2.Since some mailboxes have this issue, using PST migration is also a good option. Export emails, contacts, and calendar items to Outlook using a .pst file - Microsoft Support

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Answer 2

To remove the mailbox from on-prem Exchange without affecting the AD account, you can go with the below command-

Disable-Mailbox -Identity "user1"

This will remove the mailbox from on-prem but keep the AD account intact.

To Fix Error “Too Many Transient Failure Retries Permanent Exception" error you can go with the Xiantao recommendation.

Let me know if you have any other query.