When you delete a file in Microsoft Outlook it goes to the Deleted Items folder. The problem with the Deleted Items folder is that when you empty the deleted items folder even though the messages are deleted the space is not freed up on your hard drive. To get back wasted space in an Outlook PST file:
Open Microsoft Outlook
Go to the File menu and select Data File Management
Highlight a PST file, for example the one for Deleted Items
How to compact a folder in Microsoft Outlook
Linear Mode
