Ways to avoid malware and harmful apps on Mac
Some software is harmful and can cause problems for your Mac. Frequently, harmful apps are disguised as a movie or graphics file. These apps, called trojans, are most often spread by internet downloads and email attachments.
Important: If you see a warning that a file you received is an app — for example, a file sent to you in an email — and you don’t expect the file to be an app, don’t open the file. Delete it from your Mac.
Here are some tips to protect your Mac from harmful apps:
Never download unlicensed or "pirated" software from the internet.
Only use apps from a known and trusted source. You can limit the types of apps that open on your Mac using Security & Privacy preferences. See Protect your Mac from malware.
To reduce exposure to harmful apps or files, limit the number of administrator users you create. Consider creating a standard user for your daily work and use the administrator user only when you need to install software or administer users.
Make sure your Mac is updated to the latest software. To check for available updates, choose Apple menu > System Preferences, then click Software Update .