This guide will cover the issue where your recipients are getting .dat files instead of the intended format in Outlook 2007.


The cause of this is due to Outlook sending out emails in a Rich Text format.


Send your messages in either HTML or plain text format.

Send messages in HTML or plain text format

  1. On the Tools menu, click Options, and then click Mail Format.

  2. Under Message Format, in the Compose in this message format list, click HTML or Plain Text.

  3. Click OK.