Hi, i have the same problem with the current dovecot version 2.2.22. I wonder that nobody else seems to have run into this, since this thread is quite old.
Did i miss something and does one need a special configuration for syncing public namespaces? Markus, do you still use your patch or did you encounter some problems with it? I just tested it and it still seems to work: the logs have many "Error: Couldn't create lock /[..]/dovecot-sync.lock: Permission denied" entries now, which is always better than thousands of duplicate mails ... Best, Georg.
