Quite simple I believe

 move all files in you Queue and Scratch folder, and it will stop.

Why did could happen could be obvious, although you protected the mailboxes with strong password, you could have installed an open relay with MercuryS

Goto Configuration -> MercuryS SMTP server and then  to Connection control

Make sure that at least the first to  options are activated, If you do not want to send mail through you server from the outside to the outside, you can leave it like that.

More info in the online help en on this site

kind reagrds 

Marc

It appears my mercury server has been bot attacked and is spamming out emails without my permission. I have the server turned off at the moment and have changed all passwords on each account on the system but when I restart Mercury it goes right back to auto spamming. How can I flush out all in system emails and figure out how the bot got permission to send email through my system?  The system only has 4 accounts on it. All are password protected with 11 char, combo alternating alpha/numeric Ucase Lcase & 1 special char each. I am running v4.62 of mercury on W2k Server w/All SPs.