As LOTR has already pointed out, I don't think we'll ever see integrated antivirus in LW. Just think about it:
-they'd have to keep a constant update on virus definitions=more developers=more money needed=price skyrocketting
-even if they asked already existant Antivirus developing companies to give them virus definitions, they'd still have to pay for them (most probably and they can't magically come up with money=more money needed=price skyrocketting
-they've already integrated a built-in mp3 player which (no offence) isn't exactly cutting edge. If they integrated Antivirus, either it would be as cutting edge as the mp3 player ("dull" edge then), or they would put some serious effort on it and take in more developers=more money needed=price skyrocketting.
I personally have Norton Antivirus' Autoprotect feature always on and it works (almost) seamlessly in the background. I really notice it only when I insert a disc or do a disc mount. So why not just do that. You'd pay more money anyway for that integrated Antivirus, so why not pay it for a dedicated software and give LW's developers more time to think about how to improve LW programing?

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