Admin menu item is missing
Admin menu items are controlled by two factors:
If you are logged into Admin with a user whose profile doesn’t have access to that page, then the menu option won’t display for you.
See Admin Profiles for more information.
Text strings defined to display the item
Menu options don’t display if the
BOX_ constants for them aren’t defined.
These constants are defined in various places:
/includes/filenames.php(for core system files, not plugins)
/admin/includes/languages/english.php(for core system files, not plugins)
(And for other languages, consult the corresponding language directories/files.)