Yesterday I updated to WP 3.6 and since then a popup appears when we enter in every page!... Our site is http://www.arqcoop.com.
I've turned off all plugins, still no good... I only have 4 plugins: Akismet, Blogger Importer, Hello Dolly and WordPress Importer.
I've run trough all kind of foruns and I don't see any answer to this problema...