List Exchange 2010 Mailbox Sizes

Step 1: Login to your Exchange 2010 server

Step 2: Run Exchange PowerShell as Administrator

Step 3: Run PowerShell string

Get-MailboxStatistics -Database “Mailbox Database XXXXXXXXXXXXX” | Select DisplayName, ItemCount, TotalItemSize | Sort-Object TotalItemSize -Descending | Export-CSV C:\temp\MBSizes.csv

Alter the mailbox database number and the export address as required.