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…
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Figuring out how to check a file for viruses can be nerve-wracking, and when you’re worried about a virus or malware 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 computer and online.
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There are many situations where you’ll need 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 might want to scan a file from an unfamiliar website before you download it to your computer.
In this guide, we’ll walk you through tools you can use to scan a file for viruses directly on your computer and how to check a file for viruses online.
If you’re using Windows, you have access to a built-in antivirus tool called Windows Security, also known as Windows Defender. Here are the steps to use Windows Security to scan a file for viruses on your computer on Windows 11:
VirusTotal is a good option if you want to scan a file for viruses online. It uses a variety of antivirus databases from different security vendors. Keep in mind, though, that you shouldn’t upload files containing personal or sensitive information.
Here are the steps to upload and scan a file:
After you scan a file for viruses, 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 check.
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.
If it’s from a legitimate software company, such as Microsoft, this should be listed. 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.
False positive results are possible when using antivirus software file checkers. If you know you want to use a file and think it’s safe, you might consider testing it in a sandbox, a virtual environment that’s kept separate from the rest of your computer.
Antivirus apps such as Avast offer sandbox environments so you can safely test files and run applications without putting your device at risk.
If you have suspicions about a file, you should continue to monitor its activity on your device, even if you’ve taken these precautions – and using an antivirus app can help you monitor activity in real time.
If it finds a threat, antivirus apps generally isolate the file from the rest of your files by placing it in quarantine. This stops the file from interacting with anything else on your device and protects your other files and data from being compromised.
Once a file is in quarantine, your antivirus app will 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 since there may be other files that were infected.
You can also schedule regular automatic scans in your antivirus app, so you never have to remember to run a scan manually.
There are a number of excellent antivirus apps on the market, many of which offer more features than built-in tools like Windows Security and which will support multiple devices with a single subscription. Here are our top five picks:
Check out our guide to the best antivirus software for more details on these options and other file scanners.
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 or want to learn more about viruses and antivirus software:
With the growing number of threats online, we all need to be vigilant. If you’re concerned about the safety of a file you’ve downloaded, it’s a good idea to scan the file for viruses before you open it.
On a Windows computer, scanning a single file is simple – you can use a custom scan in Windows Security to locate and scan the file for threats.
If you want to scan a file for viruses online, VirusTotal is a great online file scanner. You can upload almost any kind of file, and VirusTotal will check it using data from a wide 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 safe or remove them – and however you scan your files for viruses, it’s wise to use an antivirus app to regularly scan your device.
There are several ways to scan a file for viruses. You can use Windows Security to perform a custom scan for viruses on a Windows 10 or 11 computer. You can also scan a file using one of the many commercial antivirus options available for PC, Mac, iOS, and Android, or you can use an online option such as VirusTotal.
VirusTotal is a leading option to check a file for viruses online. You can upload almost any file type, and VirusTotal will check it using the latest malware data from a wide range of antivirus providers. You can also use VirusTotal to check suspicious websites before you access them.
Yes, and if you have any concerns about a file, you should certainly check it before you download it. Many antivirus apps have plug-ins you can install in your web browser that monitor online activity automatically and allow you to scan links before you download files to your device.
Viruses are part of a category of computer programs called malicious software – or “malware” – which target data on your device. Like biological viruses, computer viruses can replicate themselves and spread between files and devices. Viruses are often disguised as files that appear harmless but can compromise your data and details and damage your device.
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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.
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