i use lavasoft's adwatch real-time antimalware. one question that has bothered me, but never dispositively resolved, is whether this lavasoft real-time conflicts with windows defender.

i think defender does an excellent job. if the adwatch purview intersects that of defender then what will be the symptoms?

Having two real-time shields of the same type can cause conflict. You situation is a perfect example. I recommend only having one of those on. Out of the two, I would leave on Ad-watch.

Regards,
David.