Thanks riverco for the helpful answer. Just my two cents:
*) First of all, it's a warning message, it doesn't impact your mail services.
*) Dovecot-2.2 deprecates plugin 'autocreate', and use "mailbox { auto }" instead. You can update your Dovecot config file to avoid this warning message if you want.
As @riverco mentions, you have to comment out all "autocreate =" and "autosubscribe =" lines, AND remove "autocreate" plugin name in "mail_plugins =" (both "protocol lda {}" and "protocol imap {}" blocks). Then, find below settings in dovecot.conf:
namespace {
type = private
separator = /
prefix =
#location defaults to mail_location.
inbox = yes
}
Now add below lines INSIDE this "namespace {}" block like below:
mailbox Sent {
auto = subscribe
special_use = \Sent
}
mailbox Drafts {
auto = subscribe
special_use = \Drafts
}
mailbox Trash {
auto = subscribe
special_use = \Trash
}
mailbox Junk {
auto = subscribe
special_use = \Junk
}
The final settings looks like below:
namespace {
type = private
separator = /
prefix =
#location defaults to mail_location.
inbox = yes
mailbox Sent {
auto = subscribe
special_use = \Sent
}
mailbox Drafts {
auto = subscribe
special_use = \Drafts
}
mailbox Trash {
auto = subscribe
special_use = \Trash
}
mailbox Junk {
auto = subscribe
special_use = \Junk
}
}
Please let me know whether it works for you. You can test it with below steps:
*) Create a new testing mail user.
*) Configure your mail client like Outlook, Thunderbird to use this testing mail user. WARNING: Do NOT use Roundcube webmail, because it will create those default mail folders by default.
*) After you have mail client configured, check whether those mail folders (Sent, Trash, Drafts, Junk) are created automatically. If yes, that means your Dovecot config file was updated successfully. if not, please let me know, we have to fix it.