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There would not be such a reason so much on mac for this type of software, due to the fact that OS X does not rune on a registry type system. All applications have preferences and for any of the preferences to be modified you would have to authenticate the action.
 
hijacked on a mac

I don't understand the inner workings stuff, but all the contacts on my yahoo mail account got contacted by someone and then they got deleted. Was that a problem that was the result of malware I have on my Mac? If so, how to I get rid of it?
 
malware on a mac?

unless u agreed to a program to install something and entering a user password i find that unlikely. Sounds like sumone signed onto a yahoo account with a saved password and just deleted the account just to be a jerk.
 
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