Switch mailboxes to Office 365 in a Hybrid deployment

Problem:

You want to know how to switch on-premises Exchange mailboxes to Office 365 and make them available permanently in the cloud after a Hybrid migration.

Solution:

The below steps describe how to change the mailboxes from Exchange on-premises to Office 365.

Following the changes, your mailbox will be cloud-only on Office 365.

1. Configure the Active Directory synchronization tool for Hybrid migration
2. Create mailboxes on the Office 365 server from the Office 365 admin center
3. Migrate mailboxes from on-premises Exchange to Office 365 using EdbMails Exchange migration software
4. Disable the mailboxes on the on-premises Exchange server
   1. Launch the Exchange Management Shell (EMS) as administrator and run the command

      Disable-Mailbox -identity <UserMailbox>

      Where <UserMailbox> is a value such as email address, name, alias.

   2. Run the following cmdlet from the PowerShell to connect to Exchange online

      $LiveCred = Get-Credential
      Connect-ExchangeOnline -Credential $LiveCred

      Import the ExchangeOnline module if you get an error

      Import-Module -Name ExchangeOnlineManagement

   3. Run the following cmdlet to disable the Exchange on-premises mailbox

      Get-Mailbox <MailboxToDisable> | fl ExchangeGuid

      Where <MailboxToDisable> is the mailbox that you want to disable

   4. Copy the GUID of the mailbox that you obtain after you run the preceding script in the following form ExchangeGuid: <Number>
   5. Run the following script on the EMS

      Enable-RemoteMailbox <UserToDisable> -RemoteRoutingAddress <UserToDisable@domain.onmicrosoft.com>

      Paste the GUID value that you obtained in the preceding step

      Set-RemoteMailbox <UserToDisable> -ExchangeGuid <Number>

      Where <Number> is the GUID’s long string of alphabets and numbers.