Late last Century Norton which started out as a Mac Toolbox Software. A Toolbox for anything I have ever experienced. Drop in a "floppy", fire it up and in short order System Fixed, Ills Cured, Drive Defragged and everything was wonderful afterwards. Then when it became unnecessary for Macs to need that kind of thing . . . Norton when to the "Dark Side". Then the degradation of the tools, the adoption of "Evil Ways" and hence the bad reputation.
I have been running Bitdefender for the past 79:42:31secs, having gone through 28,153,421 files so far from four 2TB Drives in my MacPro Editing Station. So far it's found and resolved 85 very buried Boogiemen. And it updates the Virus Tables every half an hour. Funny thing, the Boogiemen were attached to mail sent from PCs. It strips out the bad parts leaving the good parts intact. If SPAM it gets rid of the whole thing. I love it!
One funny thing though, while working at Hughes Aerospace the Macs that they were using were just trashed. I had my Silver Zero Briefcase, which the "Guards" did not like. Since it was from Martin, pre Lockheed and was used to ship a piece of hardware that is now on Mars. Once I pulled out the Norton disc and started fixing machines, out came the handcuffs. I called them "Guards", but they were actually FBI.