Exchange 2019 on prem Can delete System Mailbox?

Hi @Alberto Catagni (Fattore Digitale) ,

Welcome to the Microsoft Q&A platform!

Based on your description, you are dealing with some system mailboxes in Exchange Server. System mailboxes, such as arbitration, monitoring, and audit log mailboxes, play a vital role in the functioning of the server. Here are what you need to know:

1. Arbitration mailboxes: These are used for tasks such as review and approval workflows. You need to move them to the new database before you can delete the old database.
2. Monitoring mailboxes: These mailboxes are tied to the specific database where they were created and do not need to be moved. They are automatically deleted when the database is deleted.
3. Audit log mailboxes: These mailboxes store administrator audit logs and In-Place eDiscovery searches. Like arbitration mailboxes, they should be moved to a new database. To identify and move these mailboxes, you can use PowerShell commands. For example, to list arbitration mailboxes, you can use:

Get-Mailbox -Arbitration | Format-List Name, DisplayName, Database

Please feel free to contact me for any updates. And if this helps, don't forget to mark it as an answer.

Best,

Jake Zhang