dovecot error: Warning: Mailbox changes caused a desync. You may want to run dsync again: Mailbox [problematic mail] mailbox_list_delete_dir conflict: Mailbox has children, delete them first

Solution to get off this error:

1.) You have to look what stands in the [problematic mail]

dsync-local(info@yourdomain.com)<mK9ZIhEtxF48VgAAVzwgkw>: Warning: Mailbox changes caused a desync. You may want to run dsync again: Mailbox sieve mailbox_list_delete_dir conflict: Mailbox has children, delete them first

In this example you can see, that the problematic mailbox is ’sieve‘. In your case it could be, seriously, another mailbox.

For Dovecot it looks like:

info@yourdomain.com
INBOX
SENT
problem.direct
sieve.sieve

So here you can see, you have two children. „Direct“ is the child of „problem“, and „sieve“ of „sieve“. If the problematic mailbox is „problem“, than you have to delete it. Delete the Folder „problem“ with direct inside and you get rid off the problem.

2.) Delete the Folder which has the child mailbox inside. In my case it is sieve.

3.) Trigger recheck of the mailbox that had the error

doveadm sync -u [E-Mail] -A tcp:[2001:DB8:a242:8e13:7256:g213:e319]:5555

4.) After a couple of minute have a look at the doveadm replicator status

doveadm replicator status '*'

username                                                                                                                                                             priority fast sync full sync success sync failed
mailbox@yourdomain.com                                                                                                                                            none     17:55:16  17:55:16  17:55:16     -     

Hurray, failed has a „-“ what means, that there was no error!