Rated 1 out of 5 stars
Apparently some are having some intermittent luck with this extension, but i'm experiencing the same problem in one of the "discussions" (one post, one reply): Thunderbird shows an RTF attachment and the winmail.dat, but does not parse either to a full message body. The reply suggests marking the message pane for viewing, which i already had.
It's a great idea, but not much help on execution.
Please consider re-evaluating the LookOut Thunderbird add-on version
1.2.2 and see if there is any improvement.