I have the same issue. Just passed my site to the client and suddenly when she logs in the menu items have disappeared. I think it only happens when you change the names of the menu items, but my client isn’t English so it’s essential to have them customized.
I have the same issue, my WP is also up to date.
Here’s what I see:
http://gyazo.com/8b98bc3ea0c83b2360582420361e5a49
E: Right now I have only activated the plugin and haven’t done any changes to the settings and suddenly none of the pages or posts are seen, it only says 404. Had to deactivate to get my site running again.
