Wordpress: How To Disable A Network Enabled Plugin For Just One Site?

WordPress Multisites are a great way to manage multiple websites from a single WordPress admin and username. One thing that can get quite confusing is the use of plugins, especially on larger networks.

With multisite there are several different ways you can activate plugins:

Put the plugin in /plugins, activate it on every site individually
Put the plugin in /plugins, use ‘network activate’ to activate it on all sites
Put the plugin in /mu-plugins, automatically activated on every site

There is an alternative to disable a network enabled plugin for only one site. The following should be placed within your theme’s functions.php template and will disable akismet on a blog with id 2:

add_filter('site_option_active_sitewide_plugins', 'modify_sitewide_plugins');

function modify_sitewide_plugins($value) {
    global $current_blog;

    if( $current_blog->blog_id == 2 ) {
        unset($value['akismet/akismet.php']);
    }

    return $value;
}