Not enough information to give an explaination, but I can tell you for
certain that if your operating system is Windows Vista, using Outlook 2003,
and you are blind copied (BCC) on a message, then it is quite possible that
you are seeing the entire e-mail (to/from/date/attachments/.etc) not being
rendered correctly. Microsoft has been made aware of the issue, but as far
as I know, there is no fix.
If the above doesn't describe your computer configuration, perhaps you will
share some basic info next time in order to get a better response from your
peers.
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)