How To Do A Virus Scan

McAfee

May 19, 2025

9 MIN READ

New online threats emerge every day, putting our personal information, money and devices at risk. In its 2024 Internet Crime Report, the Federal Bureau of Investigation reports that 859,532 complaints of suspected internet crime—including ransomware, viruses and malware, data breaches, denials of service, and other forms of cyberattack—resulted in losses of over $16 billion—a 33% increase from 2023.

That’s why it is essential to stay ahead of these threats. One way to combat these is by conducting virus scans using proven software tools that constantly monitor and check your devices while safeguarding your sensitive information. In this article, we’ll go through everything you need to know to run a scan effectively to keep your computers, phones and tablets in tip-top shape.

What does a virus scan do?

Whether you think you might have a virus on your computer or devices or just want to keep them running smoothly, it’s easy to do a virus scan.

Each antivirus program works a little differently, but in general the software will look for known malware with specific characteristics, as well as their variants that have a similar code base. Some antivirus software even checks for suspicious behavior. If the software comes across a dangerous program or piece of code, the antivirus software removes it. In some cases, a dangerous program can be replaced with a clean one from the manufacturer.

Unmistakeable signs of a virus in your device

Before doing a virus scan, it is useful to know the telltale signs of viral presence in your device. Is your device acting sluggish or having a hard time booting up? Have you noticed missing files or a lack of storage space? Have you noticed emails or messages sent from your account that you did not write? Perhaps you’ve noticed changes to your browser homepage or settings? Maybe you’re seeing unexpected pop-up windows, or experiencing crashes and other program errors. These are just some signs that your device may have a virus, but don’t get too worried yet because many of these issues can be resolved with a virus scan.

Are free virus scanner tools safe and sufficient?

Free virus scanner tools, both in web-based and downloadable formats, offer a convenient way to perform a one-time check for malware. They are most useful when you need a second opinion or are asking yourself, “do I have a virus?” after noticing something suspect.

However, it’s critical to be cautious. For one, cybercriminals often create fake “free” virus checker tools that are actually malware in disguise. If you opt for free scanning tools, it is best to lean on highly reputable cybersecurity brands. On your app store or browser, navigate to a proven online scanning tool with good reviews or a website whose URL starts with “https” to confirm you are in a secure location.

Secondly, free tools are frequently quite basic and perform only the minimum required service. If you choose to go this path, look for free trial versions that offer access to the full suite of premium features, including real-time protection, a firewall, and a VPN. This will give you a glimpse of a solution’s comprehensive, multi-layered security capability before you commit to a subscription.

Cloud-based virus solutions

If safeguarding all your computers and mobile devices individually sounds overwhelming, you can opt for comprehensive security products that protect computers, smartphones and tablets from a central, cloud-based hub, making virus prevention a breeze. Many of these modern antivirus solutions are powered by both local and cloud-based technologies to reduce the strain on your computer’s resources.

Online virus scan: A step-by-step guide

This guide will walk you through the simple steps to safely scan your computer using reliable online tools, helping you detect potential threats, and protect your personal data.

1. Choose a trusted provider

When selecting the right antivirus software, look beyond a basic virus scan and consider these key features:

Real-time protection. This is paramount, as it actively blocks threats before they can execute.
An effective solution must also have a minimal performance impact so it doesn’t slow down your device.
Look for a program with an intuitive interface that makes it easy to schedule scans and manage settings.
The best protection goes beyond a simple virus detector. It should include features such as a firewall, a secure VPN for safe browsing, and identity protection.
Look for reliable brands with positive reviews and clear privacy policies, and that provide a powerful virus scanner and proactive protection for both Android and iOS devices.

2. Initiate the scan

The process of checking for viruses depends on the device type and its operating system. Generally, however, the virus scanner will display a “Scan” button to start the process of checking your system’s files and apps.

Here are more specific tips to help you scan your computers, phones and tablets:

On a Windows computer

If you use Windows 11, go into “Settings” and drill down to the “Privacy & Security > Windows Security > Virus & Threat Protection” tab, which will indicate if there are actions needed. This hands-off function is Microsoft’s own basic antivirus solution called Windows Defender. Built directly into the operating system and enabled by default, this solution provides a baseline of protection at no extra cost for casual Windows users. However, Microsoft is the first to admit that it lags behind specialized paid products in detecting the very latest zero-day threats.

On a Mac computer

Mac computers don’t have a built-in antivirus program, so you will have to download security software to do a virus scan. As mentioned, free antivirus applications are available online, but we recommend investing in trusted software that is proven to protect you from cyberthreats.

If you decide to invest in more robust antivirus software, running a scan is usually straightforward and intuitive. For more detailed instructions, we suggest searching the software’s help menu or going online and following their step-by-step instructions.

On smartphones and tablets

Smartphones and tablets are powerful devices that you likely use for nearly every online operation in your daily life from banking, emailing, messaging, connecting, and storing personal information. This opens your mobile device to getting infected through malicious apps, especially those downloaded from unofficial stores, phishing links sent via text or email, or by connecting to compromised wi-fi networks.

Regular virus scans with a mobile security software are crucial for protecting your devices. Be aware, however, that Android and IOS operating systems merit distinct solutions.

Antivirus products for Android devices abound due to this system’s open-source foundation. However, due to Apple’s strong security model, which includes app sandboxing, traditional viruses are rare on iPhones and iPads. However, these devices are not immune to all threats. You can still fall victim to phishing scams, insecure Wi-Fi networks, and malicious configuration profiles. Signs of a compromise can include unusual calendar events, frequent browser redirects, or unexpected pop-ups.

Apple devices, however, closed platform doesn’t easily accommodate third-party applications, especially unvetted ones. You will most likely find robust and verified antivirus scanning tools on Apple’s official app store.

Scanning files and attachments safely

Before you open any downloaded file or email attachment, it’s wise to check it for threats. To perform a targeted virus scan on a single file, simply right-click the file in Windows Explorer or macOS Finder and select the “Scan” option from the context menu to run the integrated virus checker on a suspicious item.

For an added layer of security, especially involving files from unknown sources, you can use a web-based file-checking service that scans for malware. These websites let you upload a file, which is then analyzed by multiple antivirus engines. Many security-conscious email clients also automatically scan incoming attachments, but a manual scan provides crucial, final-line defense before execution.

3. Review scan results and take action

Once the scan is complete, the tool will display a report of any threats it found, including the name of the malware and the location of the infected file. If your antivirus software alerts you to a threat, don’t panic—it means the program is doing its job.

The first and most critical step is to follow the software’s instructions. It might direct you to quarantine the malicious file to isolate the file in a secure vault where it can no longer cause harm. You can then review the details of the threat provided by your virus scanner and choose to delete the file permanently, which is usually the safest option.

After the threat is handled, ensure your antivirus software and operating system are fully updated. Finally, run a new, full system virus scan to confirm that all traces of the infection have been eliminated. Regularly backing up your important data to an external drive or cloud service can also be a lifesaver in the event of a serious infection.

4. Schedule an automatic scan for continuous protection

The most effective way to maintain your device’s security is to automate your defenses. A quality antivirus suite allows you to easily schedule a regular virus scan so you’re always protected without having to do it manually. A daily quick scan is a great habit for any user; it’s fast and checks the most vulnerable parts of your system. Most antivirus products regularly scan your computer or device in the background, so a manual scan is only needed if you notice something dubious, like crashes or excessive pop-ups. You can also set regular scans on your schedule, but a weekly full scan is ideal.

Final thoughts

These days, it is essential to stay ahead of the wide variety of continuously evolving cyberthreats. Your first line of defense against these threats is to regularly conduct a virus scan. You can choose among the many free yet limited-time products or comprehensive, cloud-based solutions.

While many free versions legitimately perform their intended function, it’s critical to be cautious as these are more often baseline solutions while some are malware in disguise. They also lack the continuous, real-time protection necessary to block threats proactively.

A better option is to invest in verified, trustworthy, and all-in-one antivirus products like McAfee+ that, aside from its accurate virus scanning tool, also offers a firewall, a virtual private network, and identity protection. For complete peace of mind, upgrading to a paid solution like McAfee Total Protection is essential for proactively safeguarding your devices and data in real-time, 24/7.