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Free Antivirus Software

Top legal & free PC/Mac protection

Every computer connected to the internet is vulnerable to viruses, but you don't have to pay to stay safe while you surf. It's possible to get legal, professional-quality antivirus software and other protective programmes for free. Here's our rundown of the best free antivirus and free internet security software.

Always be careful to check any software you put on your computer is suitable and compatible with your existing set-up. No liability can be accepted for any individual problems caused by acting upon the information given.

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Five simple ways to protect yourself

Internet security software to protect your computer is a must these days. But you can boost your level of protection, without any new programs.

protect yourself
  • Even if your computer comes off the shelf with a level of protection, threats change daily. So it's imperative you keep your software up-to-date or else it's useless.

    For Windows 7, 8, 8.1 or 10, just click on 'Start', go to Control Panel and click the 'Windows Update' icon, where it will show you if there are any updates for your PC. Sadly, Microsoft is no longer releasing updates for Windows XP.

    Even dedicated antivirus software (see the best free protection) needs to be updated, and do a full system scan once a week.

    Mac (and Linux) users have slightly less to worry about in terms of viruses, as there still aren't as many floating about for them. Nonetheless, Mac users should make sure they're installing security updates, and may want to consider installing free antivirus software too.

  • cartoon character with antivirus

    With more and more of us using the web to bank online and do other sensitive tasks, coming up with solid passwords is more vital than ever.

    Don't use the same login for lots of sites. If one falls into the wrong hands, your whole online life is up for grabs. Try picking one and add a few letters related specifically to each site you're logging into.

    Ensure you change passwords frequently. You can use a free password generator to get a completely random (and very secure) password or create your own using Martin's method - see his How to have lots of passwords & remember them blog for full help.

  • Most web crime still happens via email, so be on guard when checking yours. Don't open any attachments you're not expecting, or click any random links you find in the text - see the 30+ Ways to Stop Scams for more info.

    If you're unsure if a site's legit, whack the name into Google and see what comes up. It may be listed as a bad 'un.

    Quick questions

    • How can I filter out spam?

      Most big email clients such as Google, Outlook and Yahoo! have their own filtering system to stop spam. Check your settings and make sure the filter is switched on.

      Blocking spam's not an exact science, and important emails may also be blocked. The way around this is to make sure you've added senders whose emails you'd like to receive to your 'accepted' list.

      The same goes for this site's weekly Money Tips Email - its combination of freebies, money, mortgage and debt info means it can easily get caught in spam filters. (For those that don't already get it, you can sign up here.)
    • How can I protect my email address?

      Only give out your email address to people you know. Don't post it on public internet forums (including the MSE Forums) or chat rooms. Spammers often use software robots, or 'bots', to read forums, store any email addresses they find and then spam them.
    • Can email rules block spam?

      If you download your emails to a computer, eg, using Microsoft's Outlook, you can create rules to stop common spam by entering key words, eg, VIAGRA, so those emails are automatically filtered. But spammers try to beat it through mis-spelling words or using numbers in place of letters, eg, V14GRA, so you'll have to block out other combinations too.
  • Looking for a piece of software? Find out which company makes it first and then go to its site to get it there, rather than from a third party site found via Google. For smaller free or shareware programs, try using big sites such as CNET Download, rather than just getting them from anywhere that shows up.

    For advanced downloaders (OK, nerds): when using torrents, avoid .exe files wherever possible. If you must tempt fate, make sure they're thoroughly scanned.

  • Threats to your computer come in different guises with various funky names. Collectively, they're considered malicious software, or 'malware'.

    The main types are:

    • Viruses. Hidden programs that wreak havoc. These are transmitted via websites, email attachments, directly over the internet or via any other removable media. They hide in applications or files and spread from computer to computer, generally wreaking havoc wherever they get the chance.
    • Trojans. Bugs within harmless-looking files. Trojan (horses) are hidden within a harmless-looking file (eg, a picture of a celebrity) or program (ironically, they're often dressed up as antivirus tools). They aim to trick the user into installing malicious software, like spyware or adware.
    • Worms. Can drill in via open web connections. Worms take advantage of any open internet connection. They try to sneak in and replicate on the computer. Once loaded, they often start to send spam email from your computer without your knowledge.

    Quick questions

    • Who's behind malware?

      It's a common misconception that producing computer viruses is the domain of angst-ridden teenage geeks with little to do, showing off to their equally reclusive peers. While there may have been some truth in this at the beginning, and of course it still happens, these days it's often about big criminal business.
    • What happens with stolen information?

      Cracking into your computer can reveal a breadth of information about you. It could include your bank details for ID fraud or for just directly taking your cash.

      A program could grab all the emails in your address book/contacts list to find real addresses to sell to spammers. These unsuspecting people may well then be emailed from your address.
    • What happens when a virus controls my computer?

      Some viruses allow your computer to be controlled via a 'DDOS' (distributed denial-of-service) attack. This is where a website is closed down due to simulated, simultaneous use by millions or even billions of users. This can be for political reasons, a ransom, to hurt competitors or 'just for fun'.

      Many people whose computers cause this are unaware it's happening. has been hit by such an attack. Ironically, some of the people denied access for three days could've been contributing to the closure via hidden viruses on their systems.

The banks say 'if you don't have it, you could be liable'

If you're not protected and someone gets hold of your passwords, or accesses your bank account or other financial products, you may find it harder to get your money back.

The burden of proof's on the bank to show you didn't act with due care, but it's best to be safe. For more on what to do if you think you've been defrauded, read the ID Fraud Protection guide.

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Best free antivirus software

Pay for antivirus software from biggies like Norton and Kaspersky and it'll cost you £25+ per year. Yet you can get free software which, while not quite as effective or full of features as paid-for programs, still keeps on top of threats. Regardless of which route you take, remember:

Hackers develop new bugs constantly. All these free antivirus programs offer regular updates, so make sure you get them.

It's not just about how up-to-date your software is though. If you're not using it, what's the point? Try to fit in a full 'on-demand' scan once a week, where the virus scanner goes through all the files on your hard drive. That should make sure nothing slips through the net.

Something to bear in mind. The software listed below will protect your computer from viruses, but it won't generally offer the same level of functionality as paid-for software. While some free software does include extras, if there's a specific feature you want such as Wi-Fi protection or secure shopping, it's worth checking both free and paid-for options before making a choice.

Antivirus: Free PC software downloads

There are plenty of free downloads available for Windows – here we separate the wheat from the chaff.

Microsoft Defender Antivirus: Free to those with 'genuine' Windows

Windows Defender

Microsoft Defender Antivirus comes pre-installed on all 'genuine' versions (ie, not installed on more than one computer or counterfeit) of Windows 10.

It runs in the background and tells you when you need to take specific action. You can use it anytime to search for malware if your computer isn’t working properly, but reviews are mixed on how thorough the scans are.

Kaspersky Security Cloud Free: Simple to use, offers powerful protection


Russian software firm Kaspersky offers several well-reviewed ‘Security Cloud’ software packages which offer a suite of security and antivirus functions.

The free option appears to offer strong protection against a wide range of malware foes, particularly ransomware and phishing attacks.

It allows you to add a toolbar to your internet browser which highlights potentially dangerous links on webpages. 

It’s been praised by tech site PCMag UK as a top choice for free antivirus protection.

AVG Antivirus Free: Decent protection, won't slow you down


While it's been owned by Avast since 2016, AVG Antivirus Free remains an antivirus stalwart in its own right and is seen to offer decent protection with few bells and whistles.

AVG will have little impact the performance of most systems, and while it is light on extra features it includes a file shredder that allows you to permanently destroy infected folders - plus any files you wouldn't like to see recovered by another party...

Avast Free Anitvirus: Feature-rich antivirus software

avast free antivirus

The company behind Avast Antivirus Free boasts over 400 million users, which may be due to this well-reviewed piece of software offering decent protection and a lot of features. 

One of these is called CyberCapture, which detects and analyses unusual or suspicious files based on the firm's huge database collated from its users.

Avira Free Antivirus: One of the techies' favourites


The free antivirus software of choice for many techies, Avira Free Antivirus features in the top picks of tech publications like Tech Advisor and TechRadar by being thorough and offering more than just virus detection.

If you have the know-how, it has extra features you can take advantage of, but it's best for those that know their way around a PC.

Panda Free Antivirus: Beginner-friendly with bonus features


Panda Security's free antivirus has been praised by reviewers for being easy to use, though the protection it offers was found to be so-so in independent tests. Yet it includes features not often found in (free) antivirus software.

For example, it prevents USB drives running software automatically when inserted into your computer – as well as vaccinates your own USB sticks against infection from other PCs – and a monitoring function to highlight security information about processes currently running, which have accessed the internet and those which have been blocked.

Antivirus: Free Mac downloads

There aren't as many options for macOS as there are for Windows, though the general consensus is Mac users are at less of a risk.

It's still worth protecting yourself though, as recently there's been an increasing number of viruses for Macs circulating the web.

AVG Antivirus Free: Decent protection, won't slow you down

Avast Security for Mac

While it's been owned by Avast since 2016, AVG Antivirus Free remains an antivirus stalwart in its own right and is seen to offer decent protection with few bells and whistles.

AVG will have little impact the performance of most systems, and while it is light on extra features it includes a file shredder that allows you to permanently destroy infected folders - plus any files you wouldn't like to see recovered by another party...

Sophos Home Free: Solid protection, simple to set up


Simple to set up, Sophos Home Free runs in the background, providing real-time protection and antivirus scans.

It's phishing protection in particular has been praised by tech site PCMag UK, although TechRadar found it lacking in terms of options and settings.

Avast Security For Mac: Good for malware, lots of features

Avast Security for Mac

Avast Security for Mac is available for Mac users as well as on Windows users. Tech sites PCMag UK and TechRadar both rate it for the malware protection and range of features it provides, though the former also said its phishing protection leaves something to be desired.

Bitdefender Antivirus Free Edition: No frills, decent protection

Avast Security for Mac

This no frills, free offering from the Romanian software firm is a decent free option for Mac users.

It scores particularly highly in blocking ‘malware’ and potentially dangerous URLs. 

Firewall software – do you need it?

Antivirus software isn't the only protection your computer needs. If you don't have a firewall, you're leaving all your files and sensitive information vulnerable. Effectively:

Antivirus = the border patrol checking what's allowed in.

Firewall = the fence stopping it getting to the border in the first place.

So why aren't we all going firewall mad? Well, we tend to connect to the web via a router, rather than just a modem, and routers provide a hardware firewall. Make sure yours is switched on and set to a high-enough security level. Consult the manual or search online for the make and model number if you don't know how to check.

While you're there, check you've changed your router password from its factory-set default. You'd be surprised how many connections are hacked (and how much havoc gets wreaked) because the standard password hasn't been changed. Spend a little time to get your settings right here, as router firewalls give a higher level of protection than software ones.

If you don't always connect via a router, or you're just big on online security, here are the top firewall freebies...

Firewalls: Free PC software downloads

Windows Defender Firewall: Built-in, will be enough for most

Windows Defender Firewall

Included with Microsoft Defender Antivirus, this should be enough for most people (especially those who already have router firewalls), but make sure it's switched on and your copy of Windows is up-to-date. The firewall can be set on low, medium and high levels of protection.

ZoneAlarm: Good shield, but comes with ads

The free option of this very popular firewall software gets great write-ups from tech site Techradar, which described it as ‘the best free firewall’ for Windows users.

It’s great for identifying potentially unsafe web traffic and disabling malicious software.

It’s worth noting that this free version lacks some of the options of its paid-for counterpart, such as 24/7 technical support. You’ll also have to contend with ads when using the software.

Comodo Free Firewall: Good blocker but can be intrusive


Totally free and compatible with Windows XP (32-bit) and up, Comodo Free Firewall offers a good level of protection according to Tech Advisor and TechRadar. Yet it can be intrusive, providing notifications when files have been cleared as well as blocked, but these can be turned off.

Firewalls for Macs

Application Firewall: Built-in option that does the job

Mac antivirus

Since the early days, all web-ready Macs have come with some sort of firewall as standard. Which yours offers depends on what version of OS X or macOS you're using. To turn it on/off and change the settings, go to System Preferences > Security or Security & Privacy > Firewall.

Application Firewall should provide you with adequate protection in conjunction with a decent Mac antivirus programme.

Know or use any other free antivirus packages or firewall software? Please share them in the free antivirus software forum discussion.


Adware and spyware

There are other types of malware you can find on your computer. Often legitimate developers will design programs that have useful functions, but they'll also provide the owner with useful information about you or try to sell you things.

  • Adware is malware that sneaks onto your machine and opens up pop-up windows that sell you things.

    It's easy to assume these are related to the site you were visiting, yet often they aren't. If you've closed your browser, but pop-up windows still appear on your desktop, chances are you've been infected.

  • Spyware is a more dangerous, less noticeable type of malware. It covertly grabs information from your PC and sends it back to its leader out in the cyber-ether.

    Malicious spyware programs have become much more advanced in recent years, undoubtedly due to their potential for criminal money-making, so some of yesterday's top spyware removers can no longer cope.

Basic anti-adware/spyware measures:

To put your mind at rest, you'll need to download some extra software. In the meantime, there are four basic ways to fight back:

  • If you're being troubled by adware, use a pop-up blocker to alleviate the symptoms while you find a solution. Be aware though, that not all pop-ups are bad - some sites open new windows in this way. If you want to see them, hold down CTRL while clicking the link.

  • There are a couple of legit spyware programs. Google's Desktop can send info on what you've been searching back to Google, and Alexa's toolbar can do the same. In both cases these firms want to monitor your computer to help develop their products with data about searching habits.

    Whether you allow this depends on how you want the information to be used. It's mostly harmless but does mean someone, somewhere has access to your searching habits.

  • The usual way for ad/spyware programs to get on your computer is by attaching themselves to other things you download. So make sure you check the veracity of download sources before getting files.

  • Use the add/delete function on your Control Panel to get rid of any programs you don't need any more - they may be corrupted.

Like most antivirus tools, spyware removers work by comparing what's on your machine to a list of known offenders. As ever, the top anti-ad/spyware programs are commercial, but that doesn't necessarily mean you need to buy them. Try these first:

Ad/spyware removal: Free PC downloads

Adaware Antivirus: Easy-to-use option but few free features

Adaware Antivirus provides real-time protection, blocking malware as it finds it, rather than waiting until the end of the scan, and it's easy to use. Yet reviewers have said it isn't as powerful as it could, and that most features are locked in the free version, so advise against making it your primary tool.

Malwarebytes For Windows: Good but no real-time protection

While the free version only provides real-time protection for 14 days after you download it, Malwarebytes for Windows offers powerful on-demand infection detection. Tech publications recommend using it alongside other antivirus software.

Spybot Free Edition: Easy to use but slow

Spybot logo.

Spybot Free Edition has been around since 2000, and while it's easy to use and features an immunisation tool that blocks websites known to harbour malware, reviews indicate it's fairly processor-hungry, so if your computer isn't the quickest slow it might be an unwelcome addition. Again, should be used in conjunction with antivirus software.

Ad/spyware removal: Free Mac downloads

Malwarebytes for Mac: Handy but no real-time protection


One of our top picks for adware/spyware removal on Windows, there's also a free version of Malwarebytes for Mac, which PCMag UK describes as being handy for use alongside an antivirus tool.

Macscan 3: Free, but only for 30 days

Macscan 3

SecureMac's MacScan 3 is built to detect and remove spyware, adware etc. You can get a 30-day free trial; you'll pay $49.99 (£38ish) to upgrade to a full year's protection after that if you choose to. Reviews are decent, but if it doesn't work for you, just delete it once the trial's up.

Free back-up options

We've all had moments of horror (even in this very office) where due to hardware failure, power cuts or just plain ol' silly mistakes, precious documents disappear. As more and more of our lives are committed to the digital domain, backing up data is becoming increasingly important. Since there are ways to do it free, you'll only have yourself to blame if you don't.

If your PC broke, what files would you miss most? These are the ones you should be backing up as a minimum.

Use hardware

  • If you'd rather keep more tangible copies of your files, you can store them on an external USB hard drive (or good old-fashioned CDs and DVDs if you've a CD/DVD writer). As technology marches on, the latter are getting increasingly cheap; 1TB (1,000GB) for as little as £50 if you buy online.

    For a well-reviewed site where you can find storage hardware, try MyMemory* – or Amazon has plenty of options.

  • Online storage services, or 'cloud' storage services as they're also known, use a virtual hard drive that's installed on your desktop and linked directly to your online space.

    There are a whole load of online storage services available, with many offering a fair few GB of free space - see Free Online Storage for a full list.

  • If you've already lost valuable files, there may still be hope in the form of recovery programs. Freeware programs PC InspectorPuran File RecoveryRecuva and Restoration work to recover lost files, but as you might expect, it's a bit of a lottery as to whether they're able to succeed.

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