Hello I have 2.2.18 built with:
./configure \ --prefix="$prefix" \ --bindir="$prefix/bin" \ --sbindir="$prefix/bin" \ --sysconfdir="/etc" \ --with-storages="maildir,imapc,pop3c" \ --without-vpopmail \ --without-ldap I'm attempting to sync (backup) from another Dovecot server running version 2.0.21: Both servers don't have no explicit namespaces configured and both are using the Maildir storage plugin. doveadm -Dv -o imapc_user=remote_user -o imapc_host=source.host -o imapc_port=993 -o imapc_ssl=imaps -o imapc_password=remote_pass -o imapc_features="rfc822.size fetch-headers" backup -R -u local_user imapc: All seems to go well, showing local and remote mailbox syncing without errors, then finally: dsync(mcg): Debug: brain M: Deleting mailbox 'INBOX' (GUID 59023c2a911dc255842b0000d09efc50): UIDVALIDITY changed (1355416734 -> 1438784913) dsync(mcg): Error: Mailbox INBOX sync: mailbox_delete failed: INBOX can't be deleted. No mail is synced to the local server (2.2.18) after this error halts execution. What should I be looking for, in terms of possible causes of this error? I've tried syncing on a completely fresh mailbox, which hasn't been accessed by a mail client and the same error occurs. I've seen similar reports of this error before, without clear solutions / suggestions. Help would be greatly appreciated. Thanks