Navigate the the location below in your registry and make the corresponding change.

After this happens, 'InetXP.txt', 'Pop3log.txt' and 'Smtplog.txt'. will be created in the C:\Windows\Temp\Outlook Logging directory.

Key:[HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Outlook\Options\Mail]
Value Name: Logging
Data Type: REG_DWORD
Data:1 = Logging Enabled, 0 = Logging Disabled

For More Info about interpretation of logs see: http://support.microsoft.com/support/kb/articles/Q240/3/47.ASP 

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