[Dovecot] POP users complaining about multiple copies of mail

[H. Wade Minter]

Hello,

We just switched from UW to Dovecot for our mail server.  The transition went smoothly, except we have some users complaining about their email clients re-downloading mail or getting multiple copies of emails.  When we go into their accounts, we only see one copy of the email, so I'm assuming there's something odd in the communication between their client and us that's causing the mail to get downloaded repeatedly.

The clients that we've heard about are Outlook and one called "Goldmine".

Has anyone run across this before?  Scanning the archives didn't show me anything.  This is Dovecot 1.2.12-1ubuntu8 on Ubuntu 10.10.  Here's my config:

# 1.2.12: /etc/dovecot/dovecot.conf
# OS: Linux 2.6.35.4-rscloud x86_64 Ubuntu 10.10 
log_timestamp: %Y-%m-%d %H:%M:%S 
protocols: imap imaps pop3 pop3s managesieve
ssl_ca_file: /etc/ssl/certs/ca.pem
ssl_cert_file: /etc/ssl/certs/wildcard.skiltech.com.pem
ssl_key_file: /etc/ssl/private/wildcard.skiltech.com.key
disable_plaintext_auth: no
login_dir: /var/run/dovecot/login
login_executable(default): /usr/lib/dovecot/imap-login
login_executable(imap): /usr/lib/dovecot/imap-login
login_executable(pop3): /usr/lib/dovecot/pop3-login
login_executable(managesieve): /usr/lib/dovecot/managesieve-login
mail_privileged_group: mail
mbox_write_locks: fcntl dotlock
mail_executable(default): /usr/lib/dovecot/imap
mail_executable(imap): /usr/lib/dovecot/imap
mail_executable(pop3): /usr/lib/dovecot/pop3
mail_executable(managesieve): /usr/lib/dovecot/managesieve
mail_plugin_dir(default): /usr/lib/dovecot/modules/imap
mail_plugin_dir(imap): /usr/lib/dovecot/modules/imap
mail_plugin_dir(pop3): /usr/lib/dovecot/modules/pop3
mail_plugin_dir(managesieve): /usr/lib/dovecot/modules/managesieve
imap_client_workarounds(default): outlook-idle delay-newmail
imap_client_workarounds(imap): outlook-idle delay-newmail
imap_client_workarounds(pop3): 
imap_client_workarounds(managesieve): 
pop3_enable_last(default): no
pop3_enable_last(imap): no
pop3_enable_last(pop3): yes
pop3_enable_last(managesieve): no
pop3_client_workarounds(default): 
pop3_client_workarounds(imap): 
pop3_client_workarounds(pop3): outlook-no-nuls oe-ns-eoh
pop3_client_workarounds(managesieve): 
lda:
  postmaster_address: postmaster
  mail_plugins: sieve
  quota_full_tempfail: yes
  deliver_log_format: msgid=%m: %$
  rejection_reason: Your message to <%t> was automatically rejected:%n%r
auth default:
  mechanisms: plain login
  passdb:
    driver: pam
  userdb:
    driver: passwd
  socket:
    type: listen
    client:
      path: /var/spool/postfix/private/dovecot-auth
      mode: 432
      user: postfix
      group: postfix
plugin:
  sieve: ~/.dovecot.sieve
  sieve_dir: ~/sieve