Unable to View emails in MIME format?

I have been archiving my emails from Outlook. I was about to search/read some emails from a year or so ago and they came up on garbage. I get something like this followed by a bunch of garble … I guess DT doesn’t handle emails in this format?

This message is in MIME format. Since your mail reader does not understand
this format, some or all of this message may not be legible.

Content-type: text/plain;
Content-transfer-encoding: quoted-printable