Spybot S&D conflicts with Spysweeper (I run 4.5) in that it is necessary to uncheck the Internet Security Shield under the list of Internet Explorer Shields under the Summary of Shields Tab after clicking the Shields icon in the left hand column.
You can then update your immunizations, recheck the box in Shields/Summary of Shields Tab/Internet Explorer Shields/IE Security Shield.
This way the full number of immunizations sticks beyond the currently updated session.
Glib