You might notice that an attempt to install an ActiveX control (e.g. our uploader) ends up with the "An add-on for this website failed to run" error. We tried to figure out what is going on and here is what we discovered.
While preparing the next Upload Suite update, we had some support requests regarding the problems with Internet Explorer when it runs in so-called EPM (Enhanced Protection Mode). So we had to figure out what is EPM and how our uploader should live with it.