Every time when you install new Exchange servers, one default mailbox will be created. Of course, each default database has a impractical name, such as Mailbox Database 0123456789.
The most Exchange administrators don’t like default names, and like to create their own names. In some moment, you will probably want to remove default database, because “it doesn’t look nice”. You can do that on two way, renaming or removing.
With command Get-MailboxDatabase -Identity “Mailbox DatabaseName” | Set-MailboxDatabase -Name “New DatabaseName”, you can easily change database name, but path to .edb file and name will be same as old database name. If you want to rename .edb file also, you can do that by dismounting the database and running command Move-DatabasePath –Identity “NewDatabaseName” –EdbFilePath “<path>\NewDatabaseName.edb. Now mount the database with Mount-Database “NewDatabaseName”.
Otherwise, if you want to remove default database, you need to move all mailboxes from default database. Now, you surely wondering “what mailboxes when the database is new and empty”. So, although is database new, default database is not empty. First (default) Exchange database contain Arbitration, Monitoring and AuditLog mailboxes. You can easily check does that mailboxes exist in you databases.
Get-MailboxDatabase “DatabaseName” -Arbitration
Get-MailboxDatabase “DatabaseName” -Monitoring
Get-MailboxDatabase “DatabaseName” -AuditLog
When you confirm that mailboxes exist, you need to move that mailboxes to other database with commands:
Get-MailboxDatabase “DatabaseName” -Arbitration | New-MoveRequst -Target “TargetMailboxDatabase”
Get-MailboxDatabase “DatabaseName” -Monitoring | New-MoveRequst -Target “TargetMailboxDatabase”
Get-MailboxDatabase “DatabaseName” -AuditLog | New-MoveRequst -Target “TargetMailboxDatabase”
After moving to other database, you can safely remove default mailbox database.