The root user sends out some periodic mails to users. These mails get placed in /root/sent (an mbox file) instead of in /root/Maildir/.Sent/ (a Maildir directory).
It’s not a big deal, but it makes clearing the mails periodically slightly more difficult. The mails are sent via a crontab entry much like this: <command> | mutt -e 'set content_type=text/html' -s "DMR $($YDAY)" u...@kreme.com -b adminu...@kreme.com main.cf:home_mailbox = Maildir/ But I suspect the issue here is mutt and not postfix? -- ADVANCE TO THE REAR!