Here is a nice way to see who is using up the most space on your mailbox servers. Get-Mailbox -ResultSize Unlimited | Get-MailboxStatistics | Select DisplayName,TotalItemSize,ItemCount, Database,LastLogonTime,LastLoggedOnUserAccount | SortTotalItemSize -Descending | ConvertTo-Html -Title “Mailbox Stats”|Out-file “C:\MailboxStatistics.html