A small handful of my users have their e-mail being written to /var/mail/<domaina_name>_<user name> instead of being delivered to the apropriate Maildir. I haven't been able yet to determine what sets these users apart. So far it's happening to 6 users out of more than 250. I've verified that they have proper entries in /etc/passwd. I've also verified that they do appear in /etc/postfix/virtusertable, that they are listed in /etc/courier/userdb and that userdb.dat is current with userdb. I've also examined the contents of the domain top level directory and of the user directory under the domain top level directory. Any ideas as to why these few users aren't delivering normally?