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.
The problem started to appear on different computers and it was difficult to understand why some machines are working fine and others - fail. Moreover, it stopped to install even on those machines where I used to install ActiveX uploader without any issues.
We tried to install ActiveX manually, and as soon as you do it, uploader appears on a page without any problems. So it was looking like there is some problem with the .cab file. However it failed even with old versions of our ActiveX uploader, which never had any problems.
Eventually, I have found out that if you run the browser as Administator (right-click the IE icon and select an appropriate menu), the problem disappeared. There was such a problem in the past (in the days, when Windows Vista was young and modern), but it was solved by a specific .inf file entry which is already included to the uploader.
I thought that Microsoft could change their policy and started to ignore it. However they never announced that and I could not google any information about it. However I encountered this discussion:
It makes things clear. Microsoft fixed a security problem which allowed to elevate permissions and attack a computer using a malicious page, however as a side effect, they have broken all ActiveX controls - the browser just does not have enough permissions to install it because of this fix.
I hope Microsoft will eventually fix this issue, meanwhile here are some suggestions what you can do about it:
Instruct your users to run the browser "As Administrator" if they see these symptoms.
Put a link to download the standalone ActiveX installer. Just get an installer for your version in the Download Section and put it to your server and add a link, say, in the upload page footer.
Turn off ActiveX and force Upload Suite to load Java uploader on IE. You can use the type property to do it.
Migrate to HTML5 uploader instead of using Java/ActiveX. If you considered this in the past but had to abandon this idea, it makes sense to consider it again, because HTML5 uploader was greatly improved in the last year and most of Java/ActiveX features is already available there.
Feel free to contact us at firstname.lastname@example.org if you have any questions regarding this issue.