[Dovecot] Mailbox consistency with multiple clients

[Yates Ian Mr (ITCS)]

We're experiencing a problem with a shared account, where multiple users
are accessing it at the same time there seems to be a problem where the
view one user sees is not the same as the other users.  This includes
experiences such as deleted mail reappearing, moved mail not arriving at
a destination.

I'm running the latest release of dovecot (1.1.3) with the following
settings.

Any help would be appreciated.

Cheers.

# 1.1.3: /usr/local/dovecot-1.1.3/etc/dovecot.conf
base_dir: /var/run/dovecot/
log_path: /var/log/dovecot/error.log
info_log_path: /var/log/dovecot/info.log
protocols: imap imaps pop3 pop3s
ssl_cert_file: /usr/share/ssl/certs/dovecot-cert.pem
ssl_key_file: /usr/share/ssl/private/dovecot-key.pem
disable_plaintext_auth: no
login_dir: /var/run/dovecot/login
login_executable(default): /usr/local/dovecot/libexec/dovecot/imap-login
login_executable(imap): /usr/local/dovecot/libexec/dovecot/imap-login
login_executable(pop3): /usr/local/dovecot/libexec/dovecot/pop3-login
login_process_size: 16
login_processes_count: 20
login_max_processes_count: 1000
valid_chroot_dirs: /var/spool/mail:/home
max_mail_processes: 1024
verbose_proctitle: yes
mail_location: mbox:%h/Mail:INBOX=/mail/spool/%u:INDEX=/mail/cache/%u
fsync_disable: yes
maildir_copy_with_hardlinks: no
mbox_min_index_size: 200
mbox_dirty_syncs: no
mbox_lazy_writes: no
mail_executable(default): /usr/local/dovecot/libexec/dovecot/imap
mail_executable(imap): /usr/local/dovecot/libexec/dovecot/imap
mail_executable(pop3): /usr/local/dovecot/libexec/dovecot/pop3
mail_plugin_dir(default): /usr/local/dovecot-1.1.3/lib/dovecot/imap
mail_plugin_dir(imap): /usr/local/dovecot-1.1.3/lib/dovecot/imap
mail_plugin_dir(pop3): /usr/local/dovecot-1.1.3/lib/dovecot/pop3
imap_client_workarounds(default): delay-newmail outlook-idle
netscape-eoh tb-extra-mailbox-sep
imap_client_workarounds(imap): delay-newmail outlook-idle netscape-eoh
tb-extra-mailbox-sep
imap_client_workarounds(pop3):
pop3_uidl_format(default): %08Xu%08Xv
pop3_uidl_format(imap): %08Xu%08Xv
pop3_uidl_format(pop3): %08Xv%08Xu
pop3_client_workarounds(default):
pop3_client_workarounds(imap):
pop3_client_workarounds(pop3): outlook-no-nuls oe-ns-eoh
namespace:
  type: private
  inbox: yes
  list: yes
  subscriptions: yes
auth default:
  executable: /usr/local/dovecot/libexec/dovecot/dovecot-auth
  count: 50
  worker_max_count: 100
  passdb:
    driver: pam
    args: session=yes dovecot
  passdb:
    driver: passwd
  passdb:
    driver: shadow
  userdb:
    driver: passwd