[Dovecot] dovecot - outlook users keep getting locked out of imap

[Anthony Kolasny]

Greetings:

My outlook users accessing mail via dovecot's imaps have been consistantly
getting locked out of their email. It happens about once a week per
outlook user. It appears to happen when the are cliking on emails with
attachments.  When this happens, there are two imap deamons running for
that user.  I kill both deamons and things start working again.  
Squirrelmail, thunderbird and pine users haven't had this issue.  I'm 
running a version of dovecot dated dovecot-stable-20050610.

All user accounts have their mail on nfs mount points. The INBOX directory
is local to the imap server but we have a smtp server that gets this data
via nfs. Below is the dovecot.conf info:

	base_dir = /var/run/dovecot/
	protocols = imap imaps

	ssl_disable = no
	ssl_cert_file = /usr/local/imaps/certs/dovecot_cert.pem
	ssl_key_file =  /usr/local/imaps/certs/dovecot_key.pem

	disable_plaintext_auth = yes
	login_dir = /var/run/dovecot/login

	login_process_size = 128
	login_processes_count = 9
	login_max_processes_count = 256
	login_max_logging_users = 512
	verbose_proctitle = yes

	mail_extra_groups = mail
	default_mail_env = mbox:~/mail/:INBOX=/var/spool/mail/%u

	mmap_disable = no
	lock_method = fcntl

	mbox_read_locks = fcntl
	mbox_write_locks = dotlock fcntl

	mbox_lock_timeout = 300
	mbox_dotlock_change_timeout = 30
	mbox_dirty_syncs = yes
	mbox_very_dirty_syncs = no

	protocol imap {
	  imap_client_workarounds = outlook-idle
	}
  
	protocol pop3 {
	}

	auth default {
	  mechanisms = plain
	  passdb = pam
	  userdb = passwd
	  user = root
	}

Your assistance is greatly appreciated.

Thanks,
Anthony