Clock of your machine is correctly set? Before I saw a machine that has year 2032...
My computer clock is set to current time-date-year.
I did what
DavidR suggested which was to manually download and install the full virus definitions file --- and this fixed the problem for 8 days. Now I'm back to seeing the popup again many times a day while I'm on the computer.
I guess I can fix the popup issue for another period of time by doing the same thing, but that's kind of a nuisance to have to do that all the time.
rrudolph68 had the same problem (see post above), I'm wondering if this is still and issue with that user....