The information below, are only reference notes on other people’s Migrations from either onsite exchanges/sbs, or other hosted services.

With only doing 1 migration myself, from SBS2008 to O365. I have very little experience in migrating on site exchanges to the cloud..
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When migrating from a Onsite Exchange, to Office 365 is that Outlook will AutoDisover the onsite Exchange instead of Office 365. Running the below remove the AutoDiscover record.

  • Open an Exchange Management Shell as an administrator. (Elevated PowerShell)
  • Use the following command to discover the Identity name of your Autodiscover Virtual Directory. Either note or copy the values in the Identity field.
Get-AutodiscoverVirtualDirectory | fl Name, Server, InternalUrl, Identity

  • Use the following command to remove the AutoDiscover Virtual Directory. Be sure to replace the text inside the quotes with the value in the Identity field above.
Remove-AutodiscoverVirtualDirectory Identity "Insert identity value here"

  • You will have to confirm the removal by hitting Y for yes when prompted. You can double check to see if this worked properly by rerunning the command in step 2. You should get a blank result if successful.

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Once you have completed the above, and done a final cut off migration with MigWiz to make sure any remaining emails which may have been missed to disable any Exchange Services.


Reference Material:

Kirb.IT The Blog Enable Office 365 Auto-discover for Outlook in SBS 2011 Exchange Environments
serverfault SBS2011 Exchange and Outlook 2010 looking for autodiscover.extdomain.com
serverfault How do I reconfigure Exchange Autodiscover?