Mac OS Support Alert POP-UP Scam (Mac)

Also Known As: "Mac OS Support Alert" virus
Type: Mac Virus
Damage level: Medium

What is "Mac OS Support Alert"?

Many users encounter the fake "Mac OS Support Alert" virus alert message when visiting deceptive, untrustworthy websites. People generally arrive at these websites inadvertently - they are redirected to them by potentially unwanted applications (PUAs) that are installed without direct user permission.

In addition to redirects to untrustworthy websites, PUAs record personal and browsing-related data, and deliver intrusive ads.

Mac OS Support Alert scam

According to the scammers responsible for the "Mac OS Support Alert" fake virus alert, the user's computer/computer registration key is blocked.

They claim that this happened for one of the following reasons: the OS registration key is illegal; some installed software is illegal/pirated; the computer is proliferating viruses, or; the system is hacked and used from an undefined location. As stated in the "Mac OS Support Alert" pop-up window, the computer is blocked for the user's security.

To reactivate/unlock the Mac computer, users are encouraged to contact the Apple support (helpline). The website itself contains statements suggesting that the computer is infected with three viruses that might harm stored data and track financial activities.

To prevent any further damage and unblock the system, users must supposedly contact Apple security/support via the telephone number "+1-855-792-1999" provided. These statements regarding virus infections and blocked computers are simply attempts to trick people into contacting scammers and purchasing their products and services.

When contacted, the scammers claim to be 'technicians' or Apple support members. They encourage users to purchase various products and services that, according to scammers, will remove viruses, unblock computers, and so on. We strongly recommend that you ignore the "Mac OS Support Alert" virus alert.

Close this website and do not open it again. If you cannot close it normally, use Activity Monitor and terminate the entire browser process. Another way to close it is to simply restart your computer. In any case, do not restore the closed session the next time you open the browser, since this will open an identical/deceptive website or the website that led you there in the first place.

Potentially unwanted applications that cause redirects to these deceptive websites also tend to deliver intrusive advertisements - coupons, banners, surveys, and other similar ads.

These can be very annoying and affect the overall browsing experience, since they are usually displayed via tools that enable placement of third party graphical content on any site and conceal underlying content of visited websites. Furthermore, clicking these ads might lead to other untrustworthy websites or execute scripts that download and install other PUAs.

Another negative aspect of PUAs is that they are often designed to collect browsing-related data such as IP addresses, keystrokes, search queries, URLs of visited websites, and so on.

PUAs sometimes record personal/sensitive data as well. PUAs developers share the collected data with third parties (potentially, cyber criminals) who misuse it to generate revenue. Thus, having a data tracking app installed might lead to privacy/browsing safety issues or even identity theft.

Threat Summary:
Name "Mac OS Support Alert" virus
Threat Type Mac malware, Mac virus
Symptoms Your Mac became slower than normal, you see unwanted pop-up ads, you get redirected to shady websites.
Distribution methods Deceptive pop-up ads, free software installers (bundling), fake flash player installers, torrent file downloads.
Damage Internet browsing tracking (potential privacy issues), displaying of unwanted ads, redirects to shady websites, loss of private information.
Malware Removal (Mac)

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There are many similar fake virus alerts and error messages online. Some examples are Spyware Were Found On Your Mac, Error FXX000, and This Mac Computer Is BLOCKED. They might differ slightly, however, the purpose of most of these scam messages is to trick people into purchasing useless software, unnecessary services, etc.

All potentially unwanted applications are mostly similar - developers promote these apps as useful tools, but these are only attempts to give the impression of legitimacy and trick users into downloading/installing them.

How did potentially unwanted applications install on my computer?

Some unwanted apps have official websites, however, most people install them through intrusive advertisements or when developers use a deceptive marketing method called "bundling". Bundling is stealth installation of potentially unwanted applications with regular third party software that users download from the internet.

Generally, PUAs are hidden in "Advanced"/"Custom and other similar settings/options of the installation processes. Therefore, careless behaviour (such as skipped installation steps) often causes inadvertent installation of potentially unwanted applications or other problems relating to browsing safety and privacy.

How to avoid installation of potentially unwanted applications?

Avoid downloading software from untrustworthy sources, using third party downloaders, torrents, or other similar channels. Use official (and trustworthy) websites and direct links. Do not skip the software installation steps - check "Advanced", "Custom", "Manual" and other similar options or settings of the installation dialogs.

Deselect unwanted applications and only then finish the installation. If you encounter intrusive ads that redirect you to dubious websites (gambling, pornography, adult dating, and so on), check your browser for any unwanted extensions, add-ons, and plug-ins and uninstall them immediately.

Also check the list of installed programs on your computer. If your computer is already infected with PUAs, we recommend running a scan with Combo Cleaner Antivirus for macOS to automatically eliminate them.

Text presented in "Mac OS Support Alert" scam:

This computer is BLOCKED
DO not close this window and restart your computer
Your computer's registration key is Blocked
Why we blocked your computer?
This Mac OS's registration is illegal.
This Mac OS is using pirated software.
This Mac OS is sending virus over the internet.
This Mac OS is hacked or used from undefined location.
We have blocked this computer for your security.
Contact Apple helpline to reactivate your computer.


Mac is infected with (3) Viruses.
Mac OS Support Alert
Your System Detected Some Unusual Activity
It might harm your computer data and track your financial activities.
Please report this activity to +1-855-792-1999

 Appearance of "Mac OS Support Alert" scam (GIF):

Appearance of Mac OS Support Alert scam (GIF)

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How to identify a pop-up scam?

Pop-up windows with various fake messages are a common type of lures cybercriminals use. They collect sensitive personal data, trick Internet users into calling fake tech support numbers, subscribe to useless online services, invest in shady cryptocurrency schemes, etc.

While in the majority of cases these pop-ups don't infect users' devices with malware, they can cause direct monetary loss or could result in identity theft.

Cybercriminals strive to create their rogue pop-up windows to look trustworthy, however, scams typically have the following characteristics:

  • Spelling mistakes and non-professional images - Closely inspect the information displayed in a pop-up. Spelling mistakes and unprofessional images could be a sign of a scam.
  • Sense of urgency - Countdown timer with a couple of minutes on it, asking you to enter your personal information or subscribe to some online service.
  • Statements that you won something - If you haven't participated in a lottery, online competition, etc., and you see a pop-up window stating that you won.
  • Computer or mobile device scan - A pop-up window that scans your device and informs of detected issues - is undoubtedly a scam; webpages cannot perform such actions.
  • Exclusivity - Pop-up windows stating that only you are given secret access to a financial scheme that can quickly make you rich.

Example of a pop-up scam:

Example of a pop-up scam

How do pop-up scams work?

Cybercriminals and deceptive marketers usually use various advertising networks, search engine poisoning techniques, and shady websites to generate traffic to their pop-ups. Users land on their online lures after clicking on fake download buttons, using a torrent website, or simply clicking on an Internet search engine result.

Based on users' location and device information, they are presented with a scam pop-up. Lures presented in such pop-ups range from get-rich-quick schemes to fake virus scans.

How to remove fake pop-ups?

In most cases, pop-up scams do not infect users' devices with malware. If you encountered a scam pop-up, simply closing it should be enough. In some cases scam, pop-ups may be hard to close; in such cases - close your Internet browser and restart it.

In extremely rare cases, you might need to reset your Internet browser. For this, use our instructions explaining how to reset Internet browser settings.

How to prevent fake pop-ups?

To prevent seeing pop-up scams, you should visit only reputable websites. Torrent, Crack, free online movie streaming, YouTube video download, and other websites of similar reputation commonly redirect Internet users to pop-up scams.

To minimize the risk of encountering pop-up scams, you should keep your Internet browsers up-to-date and use reputable anti-malware application. For this purpose, we recommend Combo Cleaner Antivirus for macOS.

What to do if you fell for a pop-up scam?

This depends on the type of scam that you fell for. Most commonly, pop-up scams try to trick users into sending money, giving away personal information, or giving access to one's device.

  • If you sent money to scammers: You should contact your financial institution and explain that you were scammed. If informed promptly, there's a chance to get your money back.
  • If you gave away your personal information: You should change your passwords and enable two-factor authentication in all online services that you use. Visit Federal Trade Commission to report identity theft and get personalized recovery steps.
  • If you let scammers connect to your device: You should scan your computer with reputable anti-malware (we recommend Combo Cleaner Antivirus for macOS) - cyber criminals could have planted trojans, keyloggers, and other malware, don't use your computer until removing possible threats.
  • Help other Internet users: report Internet scams to Federal Trade Commission.

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About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for pcrisk.com since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

PCrisk security portal is brought by a company RCS LT. Joined forces of security researchers help educate computer users about the latest online security threats. More information about the company RCS LT.

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Removal Instructions in other languages
Malware activity

Global malware activity level today:

Medium threat activity

Increased attack rate of infections detected within the last 24 hours.

QR Code
Mac OS Support Alert virus QR code
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