Hi and thank you for your question.
Please do NOT install Scanguard - it's not a legit security program, but malware. If you are getting any popups/alerts about the same, close them out as well. Instead, you may use a FREE, reputed security program, Malwarebytes' Anti-Malware, which you may download using the following link:
Click "Download", and then download and install this program following the on-screen prompts. Done that, you may just run a scan every once in a month or so to keep your Mac free from any security threats.
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