I had the same issue with PDF-XChange Viewer, last week. PDF-XChange Viewer and Editor both use Tracker Update (TrackerUpdate.exe). See last week's series of posts regarding Tracker Update lockdown: A, B, C, D and E. Despite of the lockdown, with simply ignoring that alert, PDF-XChange Viewer could be updated successfully, or so it looked to me. Just to be sure, I downloaded and ran PDF-XChange Viewer's current installer, thus bypassing Tracker Update. As I mentioned last week, I think that it might be wise if SurfRight could have a look at HMPA's reaction to TrackerUpdate.exe.