If you get a file with a virus, it may not affect your machine, but if you send it to a friend with a PC, his or her computer could get infected. Many Mac users also don't realize that your Mac can still transmit and spread Windows-targeted viruses.

Malware for Macs exists, and antivirus software can help protect your investment. The most common threats to Mac users are still socially engineered Web sites, pirated software, and social network scams on Facebook and Twitter-all of which can contain malicious code that runs on your Mac, collects your password information, banking information, or directs you to malicious Web sites. Sophos Anti-Virus for Mac (which could use a better-branded name) runs in the background on your system and protects you from Trojan Horse programs, malicious applications, and keeps you safe from any future threats. While this is technically true, computer security is about much more than defending against potentially harmful viruses. 'But wait,' you say, 'Macs don't have viruses!' Sophos has created a home version of its popular corporate Mac antivirus solution, offering Apple users a simple and elegant way to stay virus-free.

Security expert Sophos has announced its latest antivirus product for Mac owners, and it's completely free.

Free sophos antivirus mac