It says Internet Explorer Add On Installer Security Warning. Question. It says Internet Explorer Add On Installer Security Warning Windows has blocked this software. Im trying to fix my printer and on the HP website they have a program that will try to figure out what is wrong. Windows 7 wont allow it. It says Internet Explorer Add On Installer Security Warning Windows has blocked this software because it can. Ive gone into internet options and the security tab and unchecked the thing that says download anyway if no valid certificate but it doesnt help. Does anyone know how to fix this  It makes me feel like a child. Tekken Flash Demo Version. I like to be. Thanks for your time in reading this rant. Internet Explorer Add On Installer Windows Has Blocked This Software' title='Internet Explorer Add On Installer Windows Has Blocked This Software' />when i try to install addon i get this, Internet Explorer Addon Installer Security Warning Windows has blocked this software because it cant verify publisher. Anyone who has purchased a Foscam camera in the past couple of years has undoubtedly experienced the Windows Internet Explorer Addon Installer Security Warning. Error Windows has blocked this software because it cant verify the publisher comes up. Open Internet Explorer and Press the Alt key while youre on. IE 9. http This was performed on Internet Explorer. Sign in to add this video to a. Error Windows has blocked this software. Internet Explorer Addon Installer. Windows has blocked this software.