$posts = new WP_Query(
  array(
    'numberposts' => -1,
    'taxonomy' => 'download_cats',
    'term' => $category->slug,
    'post_type' => 'downloads',
    'meta_query' => array(
array(
		                    	'key' => 'efda_thefile',
		                    	'value' => '',
		                    	'compare' => '!='
	        				)
	        			)
	                )
	            );