How to use Mac's built-in virus scanner to remove critical virus

Suggest reading this articles from a respected Contributor on this very issue

Stop unwanted Notifications - Apple Community

Phony "tech support" / "ransomware" popup… - Apple Community

annettefromedinburgh Said:

"Virus Scanner: Thanks for your quick response, Have used the Malwarebites and nothing came up, however I am still getting popups telling me I have a virus. Do you know how I can stop these? thanks Billy”

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Where did you get this Mac? All of this shouldn’t have started, if you’ve just opened it. So, if used then just return it.

As an alternative, back it all up > erase the drive > reinstall the macOS anew, and then use Migration Assistant to get it all back. See if it goes away…

Getting the macOS Back:

Two Major Thoughts:

A. Restore form a Backup:

Did you create a backup of your Mac prior to all of this occurring? Is so, then restore from the backup. If not, then take this as a learning experience, knowing to always backup your Mac, prior making any major changes to your Mac (i.e. upgrading your MacOS).

or...

B. Reinstall the macOS Anew:

The ultimate workaround would be through a new install.

Reinstalling the macOS Anew:

Try This:

1. First, Backup your Mac, then

2. Then, install your macOS Big Sur anew.

3. Finally, migrate it over from the Backup created in step 1

In Depth:

1. Back up your Mac:

Start by Creating a Time Machine Backupof my Mac. That way I could be assured that Incan recover my Mac, should I need the App back or if anything goes wrong due to the removal. So, Create a Time Machine backup of your Mac, so that you can have something to restore your Mac from, should anything go wrong with the reinstall.

2. Use a USB Bootable Installer:

Create a USB Bootable Installer for Big Sur. Delete the hard drive's partition. Then, install this macOS with. Go Here: How to Create a Bootable Installer for macOS - Apple Support.

3. Migrate and Reinstall Data and Apps:

Next migrate it over from the Time Machine Backup you created in step 1 to this new install.

Regarding Malwarebytes and its usage

There are some who shy away from using even this Application

This in Only to Inform the user of potential issues with this application

refer to below link

in case of work mandated antivirus... whi… - Apple Community

refer to posting from @John Galt

kaliyah231 wrote:

You should go to Safari settings, and then Notifications, and delete any funny websites there. Mine had something with the icon of Mac OS system settings, deleting it solved the problem.

I had first used Malware Bytes, and even bought and downloaded Intego VirusBarrier and NetBarrier, but that didn't solve the problem. so i hope this helps u !!

There is no malware here to find.

Somewhere along the path, a website or otherwise offered to send notifications, and those were accepted.

Unfortunately for this case, those proffered notifications are another way to send spam.

To both disable those unwanted spam notofications, and to prevent future prompts to send notifications, see:

Stop unwanted Notifications - Apple Community

PS: Some of the better known anti-malware was fined for selling personally-ide tofoed browsing and web-purchasing history. Too much of the add-in anti-malware can itself be difficult to distinguish from actual malware, and more generally the various add-on anti-malware apps can itself add issues and add security vulnerabilities. No pancea.

annettefromedinburgh Said:

"Virus Scanner: Hi, pretty new user of Mac and I get a popup when I turn on my Mac that I have a critical virus. I also get popups every now and agin saying I have a virus. Is there a builtin virus that I can use to try sort this? Thank you Billy"

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Troubleshooting Viruses on a Mac:

Viruses:

You wont get a virus on your Mac --so put that concern aside.

B. Malware:

Scan your Mac with Malwarebytes for Mac:

Malwarebytes searches for malware(short for (malicious software) and spyware. Those make your Mac act in a mislead manor. So scan with it, and remove what is found from the quarantine. It is created by longtime users of these forums making it the only reliable Security Software for a Mac.

Downloads:

1. Malwarebytes Anti-Malware for Mac
2. Malwarebytes Uninstaller

What browser are you using? Chrome and firefox are having malicious extensions that could cause this popups

Also for Safari I suggest checking your extensions:

Choose Safari > Settings (or Preferences), then click Extensions.

• To turn off an extension, deselect its checkbox.
• To uninstall an extension, select the extension and click the Uninstall button. If you can't determine what an extension does, or you don't expect to use it again, you should uninstall it.

You should go to Safari settings, and then Notifications, and delete any funny websites there. Mine had something with the icon of Mac OS system settings, deleting it solved the problem.

I had first used Malware Bytes, and even bought and downloaded Intego VirusBarrier and NetBarrier, but that didn't solve the problem. so i hope this helps u !!

Please follow the instructions posted by P. Phillips above. No further steps should be required to stop seeing these bogus messages.

Welcome from the co-efforts of all fellow participants

I personally say, thank you too