After so many years it is still the best

You have to make changes in core.php
Replace
if (!count($wp_ozh_adminmenu)) {
$wp_ozh_adminmenu = (array)get_option(‘ozh_adminmenu’);
unset($wp_ozh_adminmenu[0]);
}
with:

if (!is_array($wp_ozh_adminmenu) || !count($wp_ozh_adminmenu)) {
$wp_ozh_adminmenu = (array)get_option(‘ozh_adminmenu’);
unset($wp_ozh_adminmenu[0]);
}
and in adminmenu.css.php, insert
;height:24px;width:24px; in line 266