What is the X-MS-TNEF-Correlator header?It's value is a message id. Normally it is equal to the Message-ID: header but on some cases it has a different one. Why is this?any help would be greatly appreciated thanks.

http://www.experts-exchange.com/Software/Server_Software/Email_Servers/SendMail/Q_20081091.htmldrop the scroll bar to the bottom of the page. That's what you want.