Where is the Outlook OLK folder

Open regedit and look in the following registry key, depending on the version of Outlook you have

Outlook 97HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Outlook\Security
Outlook 98HKEY_CURRENT_USER\Software\Microsoft\Office\8.5\Outlook\Security
Outlook 2000HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Outlook\Security
Outlook 2002/XPHKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Security
Outlook 2003HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Security
Outlook 2007HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Security
Outlook 2010HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Security