Mailbox sizes missing from system manager on exchange 2007 2010

for some mysterious reason Microsoft has chosen to remove the convenience mailbox size you from the exchange system manager on exchange 2007 and exchange 2010.

In order to get the statistics and port them to a text file

Open exchange management shell

Copy and paste the command:

Get-MailboxStatistics | Sort-Object TotalItemSize -Descending | ft DisplayName,@{label=”TotalItemSize(KB)”;expression={$_.TotalItemSize.Value.ToKB()}},ItemCount –