Gmail HTML – How to View Email Source

This is a known issue with all of Google's services. They do not support the .eml or the less common .mht, both of which are known and established formats. In this case it has been (for years now) one area that all the others (Microsoft, Apple, Mozilla, and most of the rest of the community) are ahead of Google on. The only option, aside from convincing Google to support it, appears to be to either bear with the extra info and read it as a raw text file or to save it and open it with almost any other email client, such as Thunderbird or Outlook.

At this time the GMAIL web UI can't. The alternatives are to use a POP or IMAP client.

References
Gmail Help
http://support.google.com/mail

Gmail Help Forum
Turning conversation view OFF causing another problem: I can't see my replies in email threads.