I am a Mac user and am still not totally convince I need a product like this. However I decided it is better to be safe then sorry so I downloaded avast! Mac beta. The download and install went without any problems. You may lose connection to the Internet for a short time, during the installation. Once installed I had it scan my Home folder and it did it with no problem. When I did a full scan of my computer, I did notice that processes did slowed down. I was running several applications at the time so the slow down was not unexpected. Fortunately nothing was found. I have had it running for two days in the background and the only reason I know is the icon on the menu bar. Whether you need an antivirus software on your Mac is something only you can decide. If you do decide you need one Avast! for the Mac is not a bad choice.