• locate Outlook Secure Temp folder
  • delete contents
file locations are given in the registry
Outlook 97       HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Outlook\Security
Outlook 98       HKEY_CURRENT_USER\Software\Microsoft\Office\8.5\Outlook\Security
Outlook 2000     HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Outlook\Security
Outlook 2002/XP  HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Security
Outlook 2003     HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Security
Outlook 2007     HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Security
Outlook 2010     HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Security