Hi ! We've seen many of these reports lately - this should be fixed when <BR>Firefox 57 is released. But not everybody will be updated immediately. So, for now would you try this : Type in the address bar '''about:config''' (press Enter) Promise to be careful, if asked) Type and look for the preference : '''security.sandbox.content.level''' and set its value to '''1''' (one) (default value is 3 ) Then close and restart Firefox. Everything back to normal, or still no joy ? Note : Don't forget to change the value back, once this is fixed.