Recently one of the user reported that he did not see the mails he sent in the sentitems folder. We tried creating a new profile but that did not address the issue.
We noticed in composing new mail >options tab > save sent items to was selected as ‘Do not save’ selecting the default folder started saving the mails to the desired location.
The issue was resolved by clicking the File menu –> click the Options link . In the Options window select the Mail tab and scroll down to Save Messages section and check ” Save copies of messages in the Sent Items folder”
http://myrefspot.wordpress.com/2011/07/14/outlook-2010-sent-mails-do-not-save-in-sentitems-folder/
Senior IT Pro Trainer & Consultant focused on MS technologies relating to System Center Products SCCM, SCOM, SCO, SCSM