I was reading that Pegasus mail could open .msg files.

This not only is the file extension which MS Outlook uses, but is also used by my ISP Sonic.net.

I found the reference here:

A guide to Pegasus Mail filenames and file-extensions.

(Extensions existing in the "home mailbox directory".)

vandenbogaerde.net/pegasusmail/pf_pmfiles.html

I have not however been able to open saved email messages with the .msg file extension.

Thank You
Don R.

In early versions of Pegasus Mail, a queued outgoing message was in file with a .MSG extension. That is no longer the case. The .PMW file extension is now being used.

The .MSG extension has become a MS proprietary extension for Outlook. If someone is sending you emails with .msg files attached, Pegasus Mail can't read those. You will need Outlook, a third party viewer utility, or use an online tool.

This article might help: https://www.thewindowsclub.com/how-to-open-msg-files-without-outlook

Thanks for the help and direction.