Uninstall Avast completely. ! Free antivirus on Mac. That’s because this article shows you how we can do it. To get rid of it, it will take more effort and time to uninstall Avast from Mac. One antivirus software that seems to be a bit complicated to Uninstall is Avast! Free antivirus. One of the best ideas to help protect your Mac is to use antivirus software. However, there are times when your ass can hurt while trying to completely remove this antivirus software. This is because some antivirus software is known to be integrated and actually leaves some residue behind. So, how to delete antivirus on Mac?