Sent emails disappear and don't reach destination

Hi,

Sometimes when I send an e-mail, it does not show up in my 'sent' box and is nowhere to be found. Those specific emails do not reach its destination. When I realize I have to force quit MAIL otherwise the same happens with all following mails -although is not always that I realize, so imagine the dimension of the tragedy-

There's no pattern, no specific address, doesnt depend on attachments. I can relate it perhaps with using MAIL for long sessions.

This is an intermittent problem, most of the time the sent email is archived, but every once in a while it just disappears.

HELP?