How to Check a File for Viruses

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Figuring out how to check a file for viruses can be nerve-wracking, and when you’re worried about having a virus or malware infection on your device, the last thing you need is more stress.

Thankfully, there are some easy ways to check a file for viruses using antivirus software – both on your device and online.

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How to Scan a File for Viruses

There are many situations when you’ll want to check if a file is safe before you download or open it. Maybe a friend or colleague has sent you an attachment, but you’re not sure where it originally came from.

Alternatively, you may want to scan a file on an unfamiliar website before downloading it to your device.

In this guide, we’ll walk you through tools you can use to scan a file for viruses directly on your computer and explore how to check a file for viruses online.

How to Scan Files for Viruses on Windows with Antivirus Software

Norton is one of the best antivirus programs around, and it makes it easy to check files for viruses. Here are the steps you need to take to scan a file for malware:

  1. Open Norton

    If you don’t have an account, go to Norton, sign up for an account, and download the software. When that’s complete, open Norton on your device.

    <strong>Open Norton</strong>
  2. Go to Custom Scans

    In the main window, go to the Security tab and then Scans. Next, go to Scans and Tasks and select the Custom scan type.

    <strong>Go to Custom Scans</strong>
  3. Choose the Files or Folders to Scan

    From the Custom scan page, you can pick to scan a specific drive, folder, or file. By pressing control, you can also select multiple files to be scanned.

    <strong>Choose the Files or Folders to Scan</strong>
  4. Results Summary

    Once the scan has finished, you’ll get a Results Summary page. To leave this, just click Finish.

    If the scan has detected issues, these will be flagged in the Threats Detected pane. You can check these and then confirm whether you want to take Norton’s recommended action or actions. The file virus scan is now complete.

    <strong>Results Summary</strong>

How to Check a File for Viruses with Microsoft Defender

If you’re using Windows, you’ll have access to a built-in antivirus tool called Microsoft Defender Antivirus, also known as Windows Defender. Here are step-by-step instructions to take to scan a file for viruses on Windows 11:

  1. Windows Security

    Open Windows Security on your Windows PC and select the Microsoft Defender “Virus & Threat Protection” tool.

    <strong>Windows Security</strong>
  2. Pick a Scan

    Select “Scan options,” then “Custom scan.” Windows Security will ask you what file or folder you want to scan. Click “Select file” where relevant, and Windows Security will scan it.

    <strong>Pick a Scan</strong>
  3. Results

    If Windows Security finds a threat, it will present you with options on what to do next. If no threat is found, Windows Security will show “No current threats.” It’s determined that the file is safe, and you don’t need to take any further action – so you’re all set.


TotalAV and Norton are leading antivirus providers that both allow users to scan individual files. They can run comprehensive system scans and quick scans, and, unlike Microsoft Defender, they come with additional features to provide multi-layered security and protect against ransomware and phishing attacks.

Given this, they’re widely seen as providing more thorough protection than Microsoft Defender and other free solutions.

How to Scan a File for Viruses Online

VirusTotal is a good option if you want to scan a file for viruses online. The service uses multiple antivirus databases from different security vendors.

It’s a good file checker for virus scans, but keep in mind that you shouldn’t upload files containing potentially personal or sensitive information. Here are the steps to take to upload and scan a file:

  1. Go to VirusTotal and Pick a File

    Go to the VirusTotal website,, and upload your file. Click “Choose file” and select it on your computer, or drag and drop it into your browser window.

    <strong>Go to VirusTotal and Pick a File</strong>
  2. Scan

    VirusTotal will scan the file using the latest virus data from multiple antivirus providers.

  3. Threat Detected or All Clear

    If the service detects a threat, it’ll let you know that one or more security vendors have flagged the file as being potentially malicious. You should then use antivirus software on your computer to quarantine or remove the file – see our recommendations below to get started.

    Screenshot of VirusTotal flagging a file as malicious

    If no threat is detected, VirusTotal will let you know. The file is likely safe, and you don’t need to do anything further.

    Screenshot of VirusTotal finding no issues with a file

What to Check After Using a Virus File Scanner on a Downloaded File

After you scan a file for virus and malware indicators, you might wonder what to do next. If the scan came back clear, but you still have suspicions about the file, for example, then there are a few things to look at.

  1. Check the Publisher

    Firstly, if you’re concerned about a file, you can check to see if the file has a listed publisher. Right-click on the file and check its properties.

  2. Be Wary of .exe Files

    If the file is from a legitimate software company, such as Microsoft, then this should be listed as the publisher. If there’s no publisher shown or you don’t recognize the company, it’s best not to use the file without further research.

    “Are .exe files safe?” is a common question, and of course, you should be particularly wary of them as they’ll install full computer programs.

    <strong>Be Wary of .exe Files</strong>
  3. Run the File in a Sandbox

    False positive results are possible when using antivirus software file checkers. If you want to use a file and think it’s safe, you might consider testing it in a sandbox.

    This is a virtual environment that’s kept separate from the rest of your computer system so files and software can be run safely.

    Antivirus apps such as Avast offer sandbox environments so you can safely test files and run applications without putting your device at risk.

    <strong>Run the File in a Sandbox</strong>
  4. Continue to Monitor the File

    If you still have suspicions about a file – having scanned it, confirmed that it looks legit, and potentially run it in a sandbox environment – you can continue to monitor its activity on your device, even if you have taken these precautions.

    Using an antivirus app can help you monitor activity on your device in real time and detect potentially concerning behavior.

    Of course, it’s always sensible to be very wary of pirated software, to avoid opening suspicious emails, and to never download or access attachments from unknown individuals.

What Does a Virus Scan Do? How Can I Know If a File is Safe?

You may be wondering, what does a virus scan actually do? Antivirus software scans your computer’s memory for patterns suggesting the presence of malicious software and viruses.

Antivirus programs will generally let you select scan options, such as whether you perform a full scan, a scheduled scan, or a custom scan to scan manually-selected files.

Some premium tools will also incorporate system optimization checks into their scans, searching for apps that require security patches or software updates.

When running a scan, scanning engines check files against databases of known security threats. Many modern security packages provide real-time protection, monitoring system activity to identify malicious behavior from previously unknown malware.

This allows them to identify novel viruses and zero-day threats. They will often also scan each downloaded file to ensure it’s safe.

When antivirus apps find a threat, they generally isolate the file by placing it in quarantine. This stops the file from interacting with anything else on your system and protects your other files and data from being compromised.

Once a file is in quarantine, your antivirus app will present scan results and give you options on what to do next, such as removing the file or marking it as safe if it’s a file you trust.

If you find an infected file or folder on your device, it’s a good idea to run a full system antivirus scan with your antivirus app, as there may be other infected files on your system.

What Can Virus Scans Find?

Having covered how to check if a file has a virus, we’ll also explore just what a file virus checker can find. Virus scans can identify malware and infected files on your system. Some common types of malware and viruses include:

  • Worms – These viruses infect a system, replicate themselves, and spread via computer networks, contact books, and phishing emails.
  • Trojans – This is a type of disguised malware program that appears to be safe to use but allows hackers access to a system and its files.
  • Spyware – These tools allow third parties to track activity on your device or to control the device itself – potentially putting you at great risk.
  • Ransomware – If your system is hit by a ransomware attack, a hacker will lock your files and threaten to destroy them if you don’t pay a fee. This is particularly problematic for businesses and institutions with irreplaceable documents and data.
  • Adware – This type of software can be benign in cases in which it is provided to promote a product or service. In other cases, it may allow malicious actors to access your system, track you, or steal your files and data.

How Can You Protect Yourself From Downloading Files Infected with Malware?

There are a number of additional steps you can take to ensure you’re safe from malware files. Here are a few to keep in mind:

  • Get an antivirus – An important first step is to get a robust antivirus product that can protect your whole life online.
  • Avoid malicious sites – It makes a big difference to steer clear of untrustworthy sites that may be hosting viruses and malware. In addition, try to make sure you only download software from official app stores and trusted sources.
  • Enable phishing protection – Make sure to use tools included with your antivirus to scan emails and websites for potentially malicious files and links.
  • Scan if in doubt – If you’re ever worried about a file, it’s best to scan it immediately and, if you’re still uncertain, to quarantine or remove it.
  • Get a VPN and an ad blocker – Using a VPN will encrypt your internet connection, adding an extra layer of security. Providers like Surfshark also include ad blockers and tracker blockers, which will stop you from being exposed to adware and pop-ups that can carry harmful code.

Antivirus Software Picks to Scan Files for Viruses

There are a number of excellent antivirus apps on the market, which generally offer far more protection than built-in tools like Windows Security.

Many include additional tools such as password managers and data breach monitoring to provide multi-layered security for your device and data. They’ll also secure multiple devices with a single subscription.

Here are our AV picks for scanning download files and links:

Antivirus Software Starting Price Test Results Top Features Max Devices Free Offer
TotalAV $19/year Protection: 5.5/6, Performance: 5.5/6, Usability: 6/6 Phishing Protection, Password Manager, Optimization Tools 8 Free scan
Norton $29.99/year Protection: 6/6, Performance: 6/6, Usability: 6/6 Cloud Backups, Smart Firewall, Password Manager Unlimited 30-day trial
Trend Micro $19.95/year Protection: 6/6, Performance: 6/6, Usability: 6/6 Ransomware and Phishing Protection, Secure Browser, Folder Shield 10 Free tools, mobile security, 30-day trial
ESET $39.99/year Protection: 5.5/6, Performance: 5.5/6, Usability: 6/6 Webcam Protection, Disk Security, Payment Protection 10 30-day trial
Avast Free / $35.88/year Protection: 6/6, Performance: 6/6, Usability: 6/6 Ransomware Shield, Automatic Driver Updates, VPN 30 Free plan, 30-day trial

Check out our guide to the best antivirus software for more details on these options and other file scanners.

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  • Starting From $19.00/year
  • Starting From $29.99/year
  • Starting From $35.88/year

More Security and File-Virus Scanner Resources

Going beyond this guide, we have a range of other antivirus resources that can help you find answers, whether you’re looking for a file scanner, considering providers like AVG Antivirus, or want to learn more about viruses and antivirus software:

Summary — How To Tell If a Download Has a Virus

With the growing number of threats online, we all need to be vigilant. If you’re concerned about the safety of an item you’ve downloaded, it’s a good idea to scan the file for viruses before you open it so you can answer the question, “Is this file safe?”

On a Windows computer, scanning a single file is simple – you can use a custom scan in Norton to locate and scan the file for threats.

If you want to scan a file for viruses online, VirusTotal is a good online file scanner. You can upload almost any kind of file, and VirusTotal will check it using data from a variety of antivirus and security providers.

In the event you find a threat, you need to take action fast to protect your device. Antivirus software can help you quarantine files and test them in a safe sandbox environment so you can mark them as being safe, or you can remove them.

However you go about scanning your files for viruses, it’s wise to use an antivirus app to regularly scan your device.


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Harry Werber
Harry Werber

Harry is a veteran technology writer who focuses on software, AI and climate tech. He has worked with a range of organizations, from tech startups to enterprise organizations such as Microsoft, Dell and Vodafone. Alongside writing, Harry's experience includes roles leading teams, as well as managing projects, operations, and product development.