Hope you like it..

How to descommission the On-Prem Exchange server after the successful migration to O365.

October 21, 2018 at 11:40 am Leave a comment

When you performed a cutover or Hybrid migration to O365 , You need to uninstall the On-Prem Exchange Server. Even though MS recommends to keep at least one Exchange On-Prem Server(Does not require any license and special license available for this use cases), Some environments require them to be uninstall in that case we could follow the below steps.(Please note I have not included any screenshots because if you are reading this article you should have well familiarized with O365 Admin / EAC consoles.

• Change the DNS records internally & externally to point it to O365.
• Open EAC on Office365
• Click on Mailflow -> Open Connectors
• Disable or Delete the 2 Connectors ( Both Inbound & Outbound)
• Click on Organization and remove the O365 to Onpremises …config.
• Stop the AD Sync (Set-MsolDirSyncEnabled –EnableDirSync $false)
• Remove all the unwanted or non migrated mailboxes from the On-Prem Server
• Remove the Public Folders
  
• Remove / Disable Arbitration Mailbox ( Get-Mailbox –Arbitration )
• Optional(Remove OAB)
• Uninstall Exchange
• Re-enable ADSync (Set-MsolDirSyncEnabled –EnableDirSync $true)

http://galinlab.com/2017/07/06/decommissioning-exchange-after-cutover-migration-with-dirsyncadsync-is-enabled/Credits:

Entry filed under: Exchange and O365.