To mount and dismount an Exchange database, you can use the Exchange Management Shell (EMS) with simple PowerShell commands. To mount a database, use the command Mount-Database -Identity "DatabaseName", which brings the database online and makes it accessible to users. To dismount a database, use Dismount-Database -Identity "DatabaseName", which takes the database offline, making it u... https://www.office365tips.org/mount-dismount-exchange-database/