Apple Resources - Cleaning Up An Infected Mac

  ANY message telling you your Mac, iPad, or iPhone is
  infected is a Blatant LIE. No one can tell that from
  outside your Mac, iPad, or iPhone.

0. Recovery (if necessary) Startup Options

1. Ensure that macOS is up2date The single most important action you can take to improve your security and minimize your risk is to do all the updates (and upgrades).

2. Clear (browser) History and Website Data... Clearing (browser) History and Website Data removes links to any malicious websites - That's important.

3. Download, Install, and run Malwarebytes (free) daily to mitigate malware we get tricked into downloading. Proven Malwarebytes technology crushes the growing threat of Mac malware, including thorough malware, spyware, and virus removal. Finally, cybersecurity smart enough for the Mac.

4. Download, Install, and run CleanMyMac X (not free) daily followed by a Restart (without re-opening any windows) of your Mac CleanMyMac X is all-in-one package to awesomize your Mac. It cleans megatons of junk and makes your computer run faster. Just like it did on day one.

5. Download, Install, and run AppCleaner (free) as needed AppCleaner is a small application which allows you to thoroughly uninstall unwanted apps. Installing an application distributes many files throughout your System using space of your Hard Drive unnecessarily. AppCleaner finds all these small files and safely deletes them. Remove any Apps that Bad Guys tricked you into installing (such as Team Viewer). Remove any third party apps you installed that you no longer need. Make sure all your remaining apps are up2date. Check for unwanted browser extensions. For example: Safari > Preferences > Extensions and disable anything that should not be there.

6. Protect your Mac from malware macOS has many features that help protect your Mac and your personal information from malicious software, or malware. One common way malware is distributed is by embedding it in a harmless-looking app. You can reduce this risk by using software only from reliable sources. The settings in Security & Privacy preferences allow you to specify the sources of software installed on your Mac.

7. Change any compromised passwords Change the password on any compromised account. New paswords should be unique, long, and preferable randomly generated.

8. Review Phishing Computers don't get hacked without your participation. Do not respond to phishing attempts.

9. Objective-see Security Tools (free) Objective-See was created to provide simple, yet effective macOS security tools. Always free of charge - no strings attached!