Click on Tools, then Options, then Read. If there is a checkmark in the
box before Read all messages in plain text, click on this checkmark, then
Apply. Click on OK.
If this doesn't help, open the message and check if there's a paperclip
near the top right corner of the message. If there is, click on it and
record
the file name. Then tell us the part of the file name starting with the
last
period.