After using Nod32 for years on my Windows machines, I recently installed ESET on my Macs, and haven't noticed any drop in performance. Sooo... Last week, I beat a Mac-using friend on the head until he agreed to try ESET as well. And last night over dinner I ask, So how is it going with ESET on your Mac? "HORRIBLE!" he says. "My machine all but ground to a halt before an important conference call with a client! So I uninstalled ESET and the problems vanished." "Hmm," sez I. "That's odd. What were you running?" Well, it turns out he was running Parallels and some kind of GoToMeeting type thing. These programs, I know, can be very processor intensive. But he's got the latest, loaded MacBook Air 13" with the Core i7, 4Gigs RAM and 256GB SSD -- exactly they same machine that I'm using right now. And, while I don't run Parallels, I can't imagine this machine grinding to a halt even then -- not because of ESET. The performance loss shouldn't be more than 20%, right? So I still want to save my friend from himself. He's STILL in denial about malware on Macs, even though he recently had to take his Mac into the Genius Bar for a Mysterious Memory Problem that they removed. (They called it "a script" and cautioned him to bring the machine in if it ever exhibited similar symptoms, never using the "T" word. I told him about Flashback, informed him that even Apple's website was recommending use of an antivirus, scoffed at his worries than an AV would slow him down -- and now this!) My first thought was he came down with another infection that didn't like ESET. But says he ran a full scan when he first loaded ESET, and it found nothing. Ran Apple's new Flashback removal tool and it too found nothing. So I guess there's a reasonable chance his machine is clean for now. I told him last night that perhaps ESET for Mac needs a special setting when running Parallels, but I have looked in all the usual places and found no such warning. And now my question is, WHAT'S HE DOING WRONG? Is there indeed some special deal with Macs running Parallels? I hate to leave him to his own devices, because he's already fallen prey to one probable Trojan.