Free Antivirus Software

Top legal & free PC/Mac protection

free antivirus software

Every computer connected to the internet is vulnerable to viruses, forcing us to pay the software protection industry's charges to stay safe while we surf.

But it's possible to get legal, professional-quality antivirus and other protective software for free. Here's our rundown of the best free antivirus and free internet security software.

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.

  • 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.

  • 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 your passwords frequently. You can even use a free password generator to get a completely random (and very secure) password.

  • 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 guide).

    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.

Best free antivirus software

Pay for antivirus software from biggies like Norton and Kaspersky and it'll cost around £30 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.

Antivirus: Free PC software downloads

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

Free to those with 'genuine' Windows

Windows Defender comes pre-installed on all 'genuine' versions (ie, not installed on more than one computer or counterfeit) of Windows 8 and later.

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.

Free, only available on Windows 7

Microsoft's Security Essentials antivirus package is completely free to users of 'genuine' Windows machines, so it'll verify yours. As newer versions of Windows use Windows Defender, Microsoft Security Essentials is only for Windows 7 (XP, and more recently Vista, are no longer supported).

The software's unobtrusive and provides quick and comprehensive protection from viruses, trojans, and spyware. For casual Windows users, it feels and runs like part of the regular operating system rather than an added extra. But some experts say it's not as good as it used to be.

Feature-rich antivirus software

The company behind Avast Antivirus Free boasts hundreds of millions of users. And because it's such a well-reviewed and feature-rich piece of software, it's leapfrogged Avira's Antivirus in our rankings.

It's also added a feature called CyberCapture, which detects unusual files based on the firm's huge database collated from its millions of users.

The techies' pick of the freebies

The free antivirus software of choice for many techies,  Avira topped many tech publications' free antivirus round-ups by providing the most thorough and fastest protection.

If you have the know-how, it'll do everything you want it to, but it's best for those that know their way around a PC.

Robust protection and bonus features

Panda Security's free antivirus software has been praised by reviewers for its detection rates, and has scored better than paid-for programmes in independent tests. Plus 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 current running applications.

Good option if you don't need support

Acquired by Avast in 2016, antivirus stalwart AVG is still available as a separate piece of software.

The protection provided by AVG AntiVirus Free, is reasonably thorough but doesn't offer any real tech support.

AVG is unobtrusive, doesn't use too many resources, and will regularly auto-update. It includes LinkScanner, a real-time threat detector which checks links out when you're surfing the web (on Chrome, Firefox, Internet Explorer and Operaonly), and marks unsafe threats with red flags.

Antivirus: Free Mac downloads

There aren't as many options for OS X 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.

Simple option but lacks controls

Simple to use, Sophos Home Free runs in the background while you work, scanning files for threats whenever your Mac opens them.

It's had decent reviews in techie publications, although it has been found lacking when it comes to options and settings.

The most-used antivirus software

Avast Security for Mac is also available for Mac users (as well as on Windows), and, given its significant market share, is definitely worth considering.

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

Built-in option that should be enough for most

Windows XP, Vista, 7, 8 and 10 have a firewall built-in, which 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.

If the Windows firewall is set on high, you may need to spend some time tweaking its settings in the Control Panel to stop it becoming a nuisance. By default, it'll stop you downloading files over Skype, and it'll block a whole load of programs that download from the web.

Top performer but can be intrusive

It's totally free but you'll need to register and activate the licence by email within 30 days of installation. While  Comodo outperforms many similar offerings, it can be intrusive, especially if you just want a firewall that does its job quietly.

Firewalls for Macs

Built-in is best

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 & Privacy > Firewall.

Luckily, it's good, because as far as we can see there are no other decent free firewalls for Macs.

If you 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. Pop-ups that 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. It tracks what you do

    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 a couple of basic ways to fight back:

  • Use a pop-up blocker

    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.

  • Check whether you allowed the spyware

    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.

  • Be careful when downloading

    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.

  • Delete programs you don't use

    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

Slick option but few features for free

Adaware Antivirus quarantines malware as it finds it, rather than waiting until the end of the scan, and this new version has a pleasing user interface. On the downside, it doesn't block as much malware as previous versions, and most features are locked in the free version. If you make it your primary tool, you won't be fully protected.

Effective but no real-time protection

While the free version doesn't provide real-time protection or scheduled updates, Malwarebytes for Windows is still powerful enough to make a big difference, particularly when it comes to potentially unwanted programs (PUPs).

Easy to use but slow

Spybot's been going for a while, and while it's easy to use and features an immunisation tool that blocks websites known to harbour malware, it's always received mixed feedback. It's fairly processor-hungry, so if your computer's already slow it'll be an unwelcome addition, and it doesn't provide much in the ways of information about threats it finds.

Ad/spyware removal: Free Mac downloads

Quick and easy to use 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 Macs.

Free, but only for 30 days

SecureMac's MacScan 3 software is built to detect, isolate and remove spyware apps as well as blacklisted cookies saved on your system. You can get a 30-day free trial; you'll pay $49.99 (£38) to upgrade to a full year's protection after that if you choose to. Reviews are mixed, so if it doesn't work for you, just delete it once the trial's finished.

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.

Use online storage

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.

Software of the last resort: Recovery programs

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 lottery as to whether they actually succeed.