I have got problem in the last couple of days, after I upgraded to Yosemite on my Mac Pro (2009) When I try to close Safari windows popping up saying to upgrade to Mackeeper or "leave the page". I have never install this piece of garbage and I don't know how to get rid of it. When I search this app on my computer comes with nothing. I only can find instructions how to remove this if it's been installed. Thanks.