Now that we have everything in place and working we are ready to start moving our mailbox data to Office 365. You an of course do this in PowerShell but for this project I decided to use the Office 365 web console.
Something to remember before you start migrating your users, shared mailboxes and resource mailboxes is that the process does not copy across any configured forwards or mail flow settings. Be sure to make a note of these or have a process for setting them up once the user is migrated.
1. Check the Outlook connection status on the machine where the mailbox is to be moved. It should show the direct connection to the Exchange server. To do this hold down CTRL + right click on the Outlook icon in the notification area. Then click connection status.
2. Login to Office 365 and open the Exchange admin console
3. Click Recipients>Migration> and click +
4. Select Migrate to Exchange Online and select Remote move migration then click Next.
5. Click + to add the users that you want to add to the migration batch.
6. Select the user, click add and then OK
7. Verify the connection and then click Next
8. Confirm that the migration endpoint is hybrid.mydomain.com and click Next
9. Enter a name for the migration batch and click Next
10. Select a recipient for the migration batch report and leave the option to start the batch as Automatically start the batch. Also leave the preferred option to complete the batch as Manual Complete and click new.
11. Your new migration batch job should appear in the status window.
12. Click View Details for more information about what is happening during the migration.
13. Keep checking the status until eventually its says ‘Synced’
14. Click ‘Complete this migration batch’ then click Yes.
15. The status will change to ‘Completing’
16. You will see the a message on the Outlook client stating that Outlook needs to be restarted. Outlook is not ready to use until the migration is completed.
17. Once finished you will see the status change to completed.
19. Check the Outlook connection status again, it should show the connection is now made to the Office 365 servers.
Troubleshooting Mailbox Migrations
Stuck Mailbox
To troubleshoot this you will first need to connect to Office 365 using PowerShell. (This can be done in the console but I found it to be unresponsive sometimes).
If you have connected to Office 365 before then you just need to run:
$UserCredential = Get-Credential Connect-MsolService -Credential $UserCredential $exchangeSession = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri "https://outlook.office365.com/powershell-liveid/" -Credential $UserCredential -Authentication "Basic" -AllowRedirection Import-PSSession $exchangeSession -DisableNameChecking
If you have not connected to Office 365 via PowerShell before run the below after disabling the web proxy on your machine:
Set-ExecutionPolicy -ExecutionPolicy Unrestricted Register-PSRepository -Default Get-PSRepository Install-Module MSOnline $UserCredential = Get-Credential Connect-MsolService -Credential $UserCredential $exchangeSession = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri "https://outlook.office365.com/powershell-liveid/" -Credential $UserCredential -Authentication "Basic" -AllowRedirection Import-PSSession $exchangeSession -DisableNameChecking
1. If a mailbox move appears to be stuck and has been completing or syncing for an extended period of time (with no meaningful log data) you will need to take action.
2. To see the status of a particular migration batch run:
get-migrationbatch "Migrate o365user3"
3. To stop the migration batch run:
Stop-MigrationBatch -identity "Migrate o365user3"
4. To remove the migration batch run:
Remove-migrationbatch -identity "Migrate o365user3"
5. To see all outstanding migration batches run:
Get-MigrationUser
The job has been paused temporarily due to unfavorable server health, with request throttling state: ‘StalledDueToTarget_DiskLatency’.
It seems that this is resource based throttling in the O365 network and there’s nothing you can do about it (but wait) https://blogs.technet.microsoft.com/exchange/2018/06/25/resource-based-throttling-and-prioritization-in-exchange-online-migrations/
Just be aware that when migrating you may see it from time to time, if they are experiencing a heavy load at their end. I have found that these tend to get stuck, if they do just use the above process to stop the job and remove it so you can start again.
Missing SMTP Address
You see the below error:
The target mailbox doesn’t have an SMTP proxy matching ‘mydomain.mail.onmicrosoft.com’.
This is because the user does not have an @mydomain.mail.onmicrosoft.com address in their on-premise mailbox. Add the smtp address, remove the batch job (as above) and create a new migration batch.
Username & Password Prompt
When you Outlook on the client, the client may prompt for a username and password. This is normal and documented by Microsoft here.
The resolution has been implemented as a Group Policy Registry Preference and is as follows:
1. Exit Outlook.
2. Start Registry Editor
3. In Registry Editor, locate and then click the following registry subkey:
HKEY_CURRENT_USER\Software\Microsoft\Exchange
4. On the Edit menu, point to New, and then click DWORD Value.
5. Type AlwaysUseMSOAuthForAutoDiscover, and then press Enter.
6. Right-click AlwaysUseMSOAuthForAutoDiscover, and then click Modify.
7. In the Value data box, type 1, and then click OK.
8. Exit Registry Editor.
I rolled this out as a GPO Preference for all users.
