MS Outlook 2010

• Go to File > Options.
• Click Advanced in the left frame.
• In the right frame, check the Enable troubleshooting logging option in the Other section.
• Click OK.
• Restart MS Outlook. 
  

MS Outlook 2007 and older

1. Expand Tools > click Options.
2. Open the Other tab.
3. Click Advanced Options.
4. Select the Enable logging (troubleshooting) option.
5. Click OK twice.
6. Restart MS Outlook.

Once this option is enabled, the application troubleshooting log starts registering all information about interaction between MS Outlook 2003 / 2007 / 2010 and a mail server each time a message is sent or received. 

Please note

Do not leave logging enabled after troubleshooting. Otherwise, the log file will kconsume a lot of disk space. 

• For POP3, SMTP, and MAPI protocols:

%temp%\Outlook Logging\Opmlog.log

• For IMAP protocol:

%temp%\Outlook Logging\IMAP-usernamedomainname-date-time.log