On the Download Controls tab, there is an option "Download only unread mail (i.e. new since the last connection)"

I'm assuming this is the option you are talking about. If it isn't, then I suggest you look at this one.

Cheers

I have checked the settings and I have "download only new messages" selected but everytime Pegasus checks the server it seems to be downloading all of the messages.  It is the first time I have used pegasus email.  Is there something else I need to do?  I still want to 'leave a copy on the server' as in "outlook" so that I get the message on another computer as well.