[Dovecot] dsync error: "Mailboxes don't have unique GUIDs"

[Jeff Gustafson]

	I'm getting an error backing up mailboxes. I'm using the mirror
command:

dsync -fvo mail_home=/home/users/bob mirror ssh vmail at 10.1.4.1 dsync -o
mail_home=/home/.incoming_mail_migrations/users/bob

dsync-remote(vmail): Error: Mailboxes don't have unique GUIDs:
1ef6ee37c694894d783100000581a675 is shared by INBOX and INBOX
dsync-remote(vmail): Error: command BOX-LIST failed
dsync-local(vmail): Error: Worker server's mailbox iteration failed

	The mail user doesn't yet exist on the destination yet, thus the use of
the mail_home parameter.
	I found a mailing list message where a person was having a similar
problem but I couldn't find confirmation that the issue was resolved.
	In our case, the backup goes from maildir to mdbox format (we can't to
convert to mdbox). Things seemed to be moving along, but there are quite
a few examples of dsync failing. I think the issue happens more often
with large mailboxes ( > 50GB ). 
	We're running version 2.0.13. 
	doveconf -n:

# 2.0.13: /etc/dovecot/dovecot.conf
# OS: Linux 2.6.18-274.12.1.el5 x86_64 CentOS release 5.7 (Final) 
auth_mechanisms = plain login
default_client_limit = 15000
default_process_limit = 10000
disable_plaintext_auth = no
listen = *
mail_gid = vmail
mail_location = maildir:~/Maildir
mail_plugins = zlib
mail_uid = vmail
mmap_disable = yes
namespace {
  inbox = yes
  location = 
  prefix = INBOX.
  separator = .
}
passdb {
  args = /etc/dovecot/conf.d/dovecot-sql.conf.ext
  driver = sql
}
plugin {
  zlib_save = gz
}
protocols = imap pop3
service auth {
  client_limit = 10000
  unix_listener auth-userdb {
    mode = 0666
  }
}
service imap-postlogin {
  executable = script-login /usr/bin/postlogin-imap.sh
  user = $default_internal_user
}
service imap {
  drop_priv_before_exec = yes
  executable = imap
  process_limit = 10000
}
service pop3-postlogin {
  executable = script-login /usr/bin/postlogin-pop.sh
  user = $default_internal_user
}
}
service pop3 {
  drop_priv_before_exec = yes
  executable = pop3
  process_limit = 2500
}
ssl_cert = </etc/pki/dovecot/certs/dovecot.pem
ssl_key = </etc/pki/dovecot/private/dovecot.pem
userdb {
  driver = prefetch
}
userdb {
  args = /etc/dovecot/conf.d/dovecot-sql.conf.ext
  driver = sql
}
protocol lmtp {
  mail_plugins = zlib
}
protocol lda {
  mail_plugins = zlib
}
protocol imap {
  mail_max_userip_connections = 100
  mail_plugins = zlib
}
protocol pop3 {
  mail_max_userip_connections = 30
  mail_plugins = zlib
}


...Jeff