Remove CSS and/or JS for Select2 used by WooCommerce, see http://stackoverflow.com/questions/28547598/how-to-unload-select2-script-styles-loaded-by-new-woocommerce-2-3-x.

gistfile1.txt

// Remove CSS and/or JS for Select2 used by WooCommerce, see https://gist.github.com/Willem-Siebe/c6d798ccba249d5bf080.

add_action( 'wp_enqueue_scripts', 'wsis_dequeue_stylesandscripts_select2', 100 );

function wsis_dequeue_stylesandscripts_select2() {
    if ( class_exists( 'woocommerce' ) ) {
        wp_dequeue_style( 'select2' );
        wp_deregister_style( 'select2' );

        wp_dequeue_script( 'select2');
        wp_deregister_script('select2');

    } 
} 

Yes! @eversionsystems, thanks for the tip, this code worked for me:

// Remove CSS and/or JS for Select2 used by WooCommerce, see https://gist.github.com/Willem-Siebe/c6d798ccba249d5bf080.

add_action( 'wp_print_scripts', 'wsis_dequeue_stylesandscripts_select2', 100 );

function wsis_dequeue_stylesandscripts_select2() {
    if ( class_exists( 'woocommerce' ) ) {
        wp_dequeue_style( 'select2' );
        wp_deregister_style( 'select2' );

        wp_dequeue_script( 'select2');
        wp_deregister_script('select2');

    } 
} 

I had a site running WooCommerce v2.6 and ACF Pro was failing because it was getting an old version of Select2 supplied to it. Adding this snippet to my functions.php removed it before ACF tried to add its own so it is now working!

Note that in more recent WooCommerce versions (I believe starting with 3.2 but couldn't find a hard confirmation), there is a forked version of select2 with a different name: selectWoo. So the code would then be:

// Remove CSS and/or JS for Select2 used by WooCommerce, see https://gist.github.com/Willem-Siebe/c6d798ccba249d5bf080.

add_action( 'wp_enqueue_scripts', 'wsis_dequeue_stylesandscripts_select2', 100 );

function wsis_dequeue_stylesandscripts_select2() {
    if ( class_exists( 'woocommerce' ) ) {
        wp_dequeue_style( 'selectWoo' );
        wp_deregister_style( 'selectWoo' );

        wp_dequeue_script( 'selectWoo');
        wp_deregister_script('selectWoo');
    } 
} 

This is the working code till today with latest woo version (19/11/2018 - Woo Ver: 3.5.1)

Sometimes "Select2" dont render in first page load, giving to the user a simple text field ... so I am going to sidable it in each of my new projects.

Thanks!