I pasted this code in the function.php
if ( ! function_exists( ‘woocommerce_product_loop_start’ ) ) {
/**
* Output the start of a product loop. By default this is a UL
*
* @access public
* @param bool $echo
* @return string
*/
function woocommerce_product_loop_start( $echo = true ) {
ob_start();
wc_get_template( ‘loop/loop-start.php’ );
if ( $echo )
echo ob_get_clean();
else
return ob_get_clean();
}
}