Forum Discussion
Arbitration Mailboxes not available
I have an environment with an Exchange 2013 (15.00.1497.048) and an Exchange 2019 CU14 server installed. The new 2019 server appears to be fully operational with the exception of the system mailboxes...
PrepareAd creates the AD accounts and the mailboxes. These are "hidden" so you won't see them in the GUI and you won't see them in PowerShell unless you specify that you are looking for arbitration mailboxes. You definitely shouldn't need to enable them as mailboxes. All you need to do is migrate them to a mailbox database on the new server
Set-ADServerSettings -ViewEntireForest $True
Get-Mailbox -Arbitration | New-MoveRequest -TargetDatabase <Ex2019DatabaseName>
If you do need to recreate them, the steps are outlined here:
https://learn.microsoft.com/en-us/exchange/architecture/mailbox-servers/recreate-arbitration-mailboxes?view=exchserver-2019
