I’ve just run into this problem after updating the plugin from version 3.5.1 to 3.5.6 on WordPress version 3.5.1 via the Plugins back-end. The plugin has entirely disappeared from the back-end and front-end of the site now. I’ve attempted to manually update as well by downloading and unpacking the zip file into wp-content/plugins. No success yet. ??
We have not changed the theme at any point.
