Migration of a user mailbox is not possible as on on-prem environment mailbox is displayed as remote mailbox but on exchange online the status is shown as not migrated

Question

Migration of a user mailbox is not possible as on on-prem environment mailbox is displayed as remote mailbox but on exchange online the status is shown as not migrated.

We tried to take full access of the mailbox, but it is not possible as it is "mail user" in on prem environment, also mailbox cannot be enabled using enable mailbox command as the status is show as mailbox has migrated.

Answer 1

Hello, @Kumar, P. ab,

Welcome to the Microsoft Q&A platform!

Based on your description, I understand that you are unable to migrate mailboxes between local Exchange environment and Exchange Online due to the different status displayed by the mailbox.

Here are a few steps you can try to resolve this:

1. Check the Attribute: Ensure that the on-premises Active Directory attributes for the user are correctly synchronized with Azure AD. Specifically, verify that the msExchMailboxGUID and other msExch attributes are correctly set or cleared as needed.
2. Remove and Recreate the Remote Mailbox: Use the “Remove-RemoteMailbox” cmdlet to remove the remote mailbox from the on-premises environment. Use the “Enable-RemoteMailbox” cmdlet to recreate the remote mailbox. This should help in syncing the correct attributes to Azure AD.
3. Verify Migration Endpoint: Ensure that the migration endpoint is correctly configured and that the MRSProxy is enabled on your on-premises Exchange server. For more information, please visit Troubleshoot migration issues in Exchange hybrid - Exchange | Microsoft Learn.
4. Check for Existing Move Requests: Sometimes, stale or incomplete move requests can cause issues. Use the “Get-MoveRequest” cmdlet to check for any existing move requests and remove them if necessary. You can click on Can't move mailboxes to Exchange Online - Exchange | Microsoft Learn for reference.
5. Sync and License: After making these changes, run a full synchronization using Azure AD Connect and then try to assign the license again.

Hopefully these steps can help you with your problems. If these steps don't resolve the issue, you might need to back up the mailbox data, remove the user from the on-premises environment, and then re-sync the user to Office 365.

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Thank you for your support and understanding.

Best Wishes,

Alex Zhang