Mektozo , Just another Contoso ! :)

Hi, It might be tricky if you want to delete the default mailbox dabase if you have a forest root Active Directory domain and Exchange server is installed in a child domain. Normally you would do the following: 1- Get all arbitration mailboxes: get-mailbox -database - arbitration 2-Move the resulting accounts to another Database: get-mailbox -database - arbitration | New-moverequest -targetdatabase But you have to do these extra steps in order to fully remove the system mailboxes and be able to remove the database: 1-Get all arbitration mailboxes using the DomainController switch specifying a DC in the Root Domain. get-mailbox -database   -domaincontroller  - arbitration 2-Move the resulting accounts to another Database: get-mailbox -database   -domaincontroller - arbitration | New-moverequest -targetdatabase -domaincontroller 3- And now you can successfully remove the database!