昨天Blinux在另一个Blog上测试cos-html-cache的缓存效果，于是乎就删除WP Super Cache，可是没想到提示UNINSTALL_WPSUPERCACHE must be set to a non-blank value in uninstall.php
UNINSTALL_WPSUPERCACHE must be set to a non-blank value in uninstall.php这句话的意思就是uninstall.php 文件中UNINSTALL_WPSUPERCACHE的值不能为空.
不管3*7=21，用记事本打开uninstall.php，直接删除下面的判断语句.

<?php
/** Include the bootstrap for setting up WordPress environment */
include( '../../../wp-load.php' );

if ( !is_user_logged_in() )
	wp_die( 'You must be logged in to run this script.' );

if ( !current_user_can( 'install_plugins' ) )
	wp_die( 'You do not have permission to run this script.' );

if ( defined( 'UNINSTALL_WPSUPERCACHE' ) )
	wp_die( 'UNINSTALL_WPSUPERCACHE set somewhere else! It must only be set in uninstall.php' );

define( 'UNINSTALL_WPSUPERCACHE', '' );

if ( !defined( 'UNINSTALL_WPSUPERCACHE' ) || constant( 'UNINSTALL_WPSUPERCACHE' ) == '' )
	wp_die( 'UNINSTALL_WPSUPERCACHE must be set to a non-blank value in uninstall.php' );

?>

然后上传覆盖原文件，这样就可以在  插件》》已安装》》wp super cache 》》卸载正常进行了。

删除完毕后，手动删除以下文件就可完全清空。

删除/wp-content/plugins/wp-super-cache目录
删除wp-content/cache目录
删除wp-content目录下的wp-config.php、advanced-cache.php
修改wp-config.php，删掉 define(’WP_CACHE’, true);
重建.htaccess