When I migrate an Exchange Server and move all the mailboxes, I regularly „forget“ to move the system mailboxes, and then I get an error when deleting the mailbox database.
Here are all the commands to find the relevant mailboxes and migrate them if necessary.
IMPORTANT: This must be done for each mailbox database because some of the monitoring mailboxes are created per database!
First of all I will show a command to get ALL mailbox databases
Get-MailboxDatabase -Status | ft name, databasesizeHere are now the commands to show the system databases
# Name of your datatbase you want to check
$Databasename = "XCHDB01"
# Get all system mailboxes for this database
Get-Mailbox -Database $Databasename -Monitoring
Get-Mailbox -Database $Databasename -AuditLog
Get-Mailbox -Database $Databasename -Arbitration
Get-Mailbox -Database $Databasename -Archive
Get-Mailbox -Database $Databasename -RemoteArchive
Get-Mailbox -Database $Databasename -PublicFolder
Get-Mailbox -Database $Databasename -AuxAuditLog
Get-Mailbox -Database $Databasename -GroupMailbox