I'm having it too. I have found that exiting Internet and entering it again seems to solve problem. That does seem to mean problem could be in my system. Not sure of status of my cache, will check it. But wow mentioned once before that she often empties cache, so maybe that is not necessarily the solution.

I have two big fat Windows books. One mentions cache, but does not say a mumbling word about emptying it or anything else about it. RTFM does not always help. That F if for funny.