1.8.1 zonefile: cannot be opened

[ѽ҉ᶬḳ℠ via Unbound-users]

With auth-zone:  zonefile: /etc/unbound/zones/root the is stating error: could not open /etc/unbound/zones/root.tmp1612: No such file or directory The directory is existent (root:root). Whether the files exists or has been created as empty file does not change the outcome.