Reconnecting Office365 mailbox to Active Directory account without AD Recycle Bin

1. 1. 1. Pause Azure AD Sync by opening Azure AD Connect. You should see this prompt
      2. Create the users new AD Account make sure that the UPN is set correct and the proxy address has an entry for SMTP:userprincipalname@domainname.com (this is the primary email address)
      3. Recover the deleted account under Users -> Deleted Users in the clients Admin portal
      4. Click on the user then select Restore
      5. Follow the prompts to set the password. ( this won’t really matter as we will be syncing it with an active directory account. )
      6. Wait for the account to restore (depending on the account size can take 15 to 45 minutes)
      7. Run the following from powershell on the client’s domain controller

   $ADUser = "username"
   $365User = "username@emaildomainname.com"
   $guid =(Get-ADUser $ADUser).Objectguid
   $immutableID=[system.convert]::ToBase64String($guid.tobytearray())
   $immutableID

   1. 8. Then connect to Microsoft online

   $credential = Get-Credential
   Connect-MsolService -Credential $credential
   $365User = “Restoreduserprincipalnamecloudonly”
   Set-MsolUser -UserPrincipalName "$365User" -ImmutableId “$null$”
   Set-MsolUser -UserPrincipalName "$365User" -ImmutableId $ImmutableID

   1. 9. Exit out of Azure AD Connect and run Start-ADSyncSyncCycle -PolicyType Delta
      10. After a few minutes the account will sync and you should see only one account in active users showing that it is synced to Active Directory.

Thanks to https://www.itpromentor.com/soft-vs-hard-match/