How to get Mailbox Size in Exchange 2007
Getting mailbox size info is very different from the simple list view in previous Exchange versions. However if you take some time and use the Powershell/Console, you can extract all the information you need.
Here is a niffty command that you can use to generate a report that will give you some statistics on your users mailbox sizes. It requests information on mailboxes greater than 1 MB and outputs the data to a txt file. You can however modify it with other various shell commands.
Get-MailboxStatistics |where {$_.TotalItemSize -gt 1MB} | sort $_.TotalItemSize |FT DisplayName,ItemCount,TotalItemSize >c:\size.txt
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