[andypl]

I do not know what the other Linux distributions, but on Debian is a problem with the autoresponder.
In the panel customer enable autoresponder system create files in the directory
When new email arrives the system creates two files .vacation.lst.lock and
.vacation.lst.gdbm
Customer ISPconfig off the autoresponder but system can not delete these files because the file is maildrop_plugin.inc.php

$file = $this->mailfilter_config_dir.'/'.$email_parts[1].'/'.$email_parts[0].'/.vacation.lock';
$file = $this->mailfilter_config_dir.'/'.$email_parts[1].'/'.$email_parts[0].'/.vacation.lst';

and should be

$file = $this->mailfilter_config_dir.'/'.$email_parts[1].'/'.$email_parts[0].'/.vacation.lst.gdbm';
$file = $this->mailfilter_config_dir.'/'.$email_parts[1].'/'.$email_parts[0].'/.vacation.lst.lock';