The Web Shield ensures that you do not inadvertently download infected files from the internet and the is also the option of scanning your system manually. There is the Mail Shield that will check incoming mail for POP3 and IMAP accounts to ensure that messages are free from infection, and the Filesystem Shield constantly monitors your computer, scanning individual files for signs of viruses. avast! is a well-known name in the antivirus field, and the company has released a beats version of its antivirus software, designed specifically with Macs in mind.Īvast! Free Antivirus for Mac beta includes three different protection shields. Windows based computers may be more at risk of viruses, but Macs are not completely immune, so the need for protection software is increasing.