I thought that system attendant is part of the past till today when I had a call with one customer.
He was trying to move a mailbox between two exchange 2013 servers and the move request fails immediately with error
"Cannot open mailbox /o=Test Lab/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Configuration/cn=Servers/cn=MY2013Server/cn=Microsoft System Attendant"
If you look at any exchange 2013 mailbox server you won’t find the famous “Microsoft Exchange System Attendant” service.
In the past this service used to handle many tasks, for example, it used to handle the offline address book generation and the mailbox move.
The new architecture for exchange 2013 depends in a new arbitration mailbox “Migration.8f3e7716-2011-43e4-96b1-aba62d229136” for mailbox move.
Knowing the architecture changes I decided to consider this error misleading and investigate the migration mailbox issue.
I found that the Migration mailbox is hosted in an offline database which is no more available due to a server crash
The solution was to recreate the mailbox again, so I first started to delete the AD object and run Setup.exe/PrepareAD to recreate the AD object again.
I’ve to run two more commands to mailbox enable the new AD object and to set the parameter management equal $true
Enable-Mailbox -Arbitration -Identity "Migration.8f3e7716-2011-43e4-96b1-aba62d229136"
Set-Mailbox "Migration.8f3e7716-2011-43e4-96b1-aba62d229136" -Arbitration –Management:$true
Move started to work and we are all happy