Even though an item may have been deleted in Outlook some remnants of it could still remain accessible in the raw data files. This setting causes Outlook 2000 and 2002 (XP) to completely remove all deleted data when it is shut down.

To enable this, follow the next steps:

1. To open the Registry Editor click on the Start button on your taskbar, then click on Run and type "regedit" and click on OK to start the utility.
   
   
2. Expand HKEY_CURRENT_USER\Software\Microsoft\Office\[office version]\Outlook\PST  (see picture 1).
   
   

   Picture 1

3. Create a new DWORD (from the menubar select Edit, point to New and select DWORD) value, or modify the existing value, called "PSTNullFreeOnClose" and set it according to the value data as above.
    
4. The modifications you made will be in effect after you reboot your PC.