Menus stop working with slider in header

Sounds like jQuery is being incorrectly loaded a second time by your theme/another plugin. Have you tried disabling your other active plugins to confirm the issue still occurs? If so, ensure the theme is loading jQuery using this PHP function (rather than loading it using a hardcoded <script>):

function theme_load_jquery() {
    wp_enqueue_script('jquery');
}
add_action('wp_head', 'theme_load_jquery');

Using this PHP method ensures that jQuery is only ever loaded once, thus avoiding issues caused by loading it twice or more.

If after this you’re still having trouble, feel free to link me to your site and I’ll take a quick look for you.

Hi again, going to mark this as resolved but feel free to get back in contact if support is still required ??