This plugin clears the cache file whenever the post/ page is saved or post_status is updated.
If plugin does not work at all and you have to turn it off manually, please delete file below by FTP client.
{your-wordpress-folder}/wp-content/qc-data/qc_active_flag.dat
View source of the webpage and if you see "WP Quick Cache" at the very end of your html then it means you are viewing cached content.