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Do you need antivirus on a Windows computer or a Mac?
Windows and macOS both come with antivirus built in: Microsoft Defender Antivirus in the Windows Security app, and XProtect on a Mac. Keep it switched on and keep the updates coming. Antivirus can't back up your files, remember your passwords or spot a scam, so those layers matter just as much.
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If we sent you this link, someone has probably told you to buy antivirus, or a trial on the computer keeps asking you to pay. Before you spend anything, know this: Windows and macOS both come with antivirus built in, and it is designed to switch itself on. This page shows what you already have, how to check it is working, and the other layers that keep a computer safe. If you’d rather have someone go through it beside you, we offer a home visit to check your computer’s protection, updates and backups.
Does Windows come with antivirus?
Yes. Every Windows 11 and Windows 10 computer has the Windows Security app, and it includes an antivirus program called Microsoft Defender Antivirus. Microsoft says the app is built into Windows and protects the computer from the moment you start it up.
Many people still call it Windows Defender. Microsoft says that in older versions of Windows 10 the app was called Windows Defender Security Center.
Windows Security is more than the antivirus. These are the parts Microsoft lists, in its own words where it gives them:
| Part | What Microsoft says it does |
|---|---|
| Virus & threat protection | Monitors threats, runs scans and gets updates to help detect the latest threats, with real-time protection settings |
| Firewall & network protection | Shows and manages the status of Windows Firewall |
| App & browser control | Microsoft Defender SmartScreen, to help protect against potentially dangerous apps, files, sites and downloads, with phishing protection |
| Account protection | Sign-in options and account settings, including Windows Hello |
| Family options | Tools to manage your family's digital life |
| Protection history | The actions Defender Antivirus has taken |
Microsoft says Defender continuously scans your device for potential threats, and that while real-time protection is off, files you open or download won’t be scanned. Its updates arrive by themselves: Windows downloads the latest security intelligence as part of Windows Update.
Does a Mac need antivirus?
A Mac has antivirus built in too. Apple says macOS includes built-in antivirus technology called XProtect, which detects and blocks known malware and can remove it, and Apple updates it automatically, separately from the big macOS updates.
Apple describes three layers working together:
- Stop it launching. The App Store, or Gatekeeper combined with notarisation. Apple says the safest place to get apps for your Mac is the App Store, and that a notarised app has been checked by Apple for malicious software.
- Block it from running. Gatekeeper, notarisation and XProtect. If macOS finds known malware, Apple says the Mac tells you the app can’t be opened and moves it to the Bin.
- Clean up if it got through. XProtect again, with extra protections on a Mac with Apple silicon to limit the damage.
Apple says these protections combine to support best-practice protection from viruses and malware. Its page on safely opening apps on your Mac (opens in a new tab) explains what the warnings mean when they appear.
On a Mac, the setting that matters is where apps can come from. In System Settings, Privacy & Security, Apple offers “App Store” or “App Store and Known Developers” next to Allow applications from. Leave it on one of those, and get software only from places you trust.
What actually keeps a computer safe?
Antivirus is one layer of five. The other four do jobs antivirus can’t, and the Australian Cyber Security Centre (ACSC), part of the Australian Signals Directorate, lists each of them in its own guides for households (opens in a new tab):
- Updates, which fix the holes malware gets in through.
- The built-in protection, Defender or XProtect, switched on.
- A backup, so a lost, broken or locked computer doesn’t take your photos with it.
- A password manager, so every account has its own strong password.
- You, not clicking, not ringing back and not handing over a code.
Just the antivirus
The built-in protection on its own: Microsoft Defender Antivirus on Windows, XProtect on a Mac. It looks for harmful software. It can't back up your files, choose your passwords or spot a scam.
All five layers
Updates close the holes malware gets in through. The built-in protection catches harmful software. A backup keeps a copy of your files somewhere else. A password manager gives every account its own password. And you don't click, ring back or hand over a code.
Updates switched off
With updates paused or no longer coming, the holes that updates fix stay open, and every other layer carries more weight. Windows lets you pause updates for up to 35 days, then they resume by themselves. A computer past its end of support gets no more updates at all.
Take any one away and the others carry more weight.
Why do updates matter so much?
Because an update closes the security holes that have been found since the last one. The ACSC explains that software updates help protect your devices by fixing coding errors and vulnerabilities, and advises turning on automatic updates as a “set and forget” setting.
Microsoft says Windows 11 downloads and installs updates automatically to keep the device secure. You can pause them for up to 35 days, and Microsoft says they resume by themselves after that. A computer that no longer gets updates at all is a different matter: the ACSC says products past their end of support no longer receive updates, and recommends upgrading. If yours is still on Windows 10, what Windows 10’s end of support means for you goes through the choices.
What can’t antivirus do?
Antivirus looks for harmful software. It can’t make a copy of your files, choose your passwords or tell a real message from a fake one.
It can’t back up your files
If the computer is lost, stolen, dropped or locked by ransomware, antivirus won’t bring your photos back. A backup will. The ACSC says backups can help you recover your data after a ransomware attack, and advises checking now and then that the backups are working.
On Windows, Microsoft’s File History makes regular backups of your files to an external drive. Open the Control Panel, select System and Security, then Save backup copies of your files with File History, and select Turn on. On a Mac, Time Machine backs up to an external drive, and Apple suggests one with at least twice your Mac’s storage. A portable backup drive is the simplest way to do either.
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| Product | What it is for | Link |
|---|---|---|
| Toshiba Canvio Advance 2TB | Portable backup drive, set up for Windows | View on Amazon for the Toshiba Canvio Advance 2TB (opens in a new tab) |
| WD My Passport for Mac 2TB | Portable backup drive, Mac-ready | View on Amazon for the WD My Passport for Mac 2TB (opens in a new tab) |
It can’t remember your passwords
One reused password, leaked from one website, opens every account that shares it. The ACSC’s advice is a passphrase of four or more random words, different for each account, and a password manager if you can’t remember them all.
You probably have one already. Apple’s Passwords app is on an iPhone, iPad and Mac, and warns about weak, reused and leaked passwords. Google Password Manager saves passwords in your Google Account, works in Chrome, and warns about compromised ones. The password manager already on your phone shows how to use whichever you have.
It can’t spot a scam for you
The ACSC describes scams as messages that try to trick you into sharing sensitive information or activating malware. The first kind needs no virus at all, just you typing in a password, reading out a code or letting someone onto the computer. Windows’ SmartScreen includes phishing protection, but no setting stops you handing details to someone who asks. The ACSC puts it plainly: no IT person, government department or business will contact you and ask for your login details.
How to check whether a text, email or website is a scam covers the signs. If an account is already behaving oddly, what to do if you think you’ve been hacked goes through it account by account.
How do I check Microsoft Defender is on?
Open Windows Security and look at the Home page. These are Microsoft’s steps, for Windows 11 and Windows 10:
-
Open Windows Security
Select Start, type Windows Security, and select it from the results.
-
Read the Home page
Microsoft says green means the device is sufficiently protected with nothing to do, yellow means a safety recommendation, and red means something that needs your immediate attention. Select anything yellow or red and follow what it says.
-
Check real-time protection
Select Virus & threat protection, then Manage settings, and check Real-time protection is On.
-
Get the latest updates
Back in Virus & threat protection, select Protection updates, then Check for updates.
-
Run a quick scan
In Virus & threat protection, select Quick scan. Microsoft says a quick scan is useful when you don't want to spend the time on a full scan of every file.
If real-time protection has been switched off, Microsoft says it turns back on by itself after a short while. The ACSC still advises checking it, because it can be switched off for a time. Microsoft’s overview of the Windows Security app (opens in a new tab) explains each part.
While you’re there, check Windows itself is updating. Select Start, then Settings, then Windows Update, and select Check for Windows updates. If any are waiting, select Download & install, and restart if it asks.
How do I check a Mac is updating?
On a Mac, choose System Settings from the Apple menu, select General, then Software Update. Apple’s steps for automatic updates are to click the Info button next to Automatic Updates and turn on the options you want, then click Done. The three options Apple lists are Download new updates when available, Install macOS updates, and Install Security Responses and system files. Turn on all three, and keep a laptop plugged in so it can download them.
Should you pay for a security suite?
That’s your choice: none of the Microsoft or Apple pages we read says you need one. If you’d rather pay for a suite from a known maker, two things matter more than which one you pick.
- Run one antivirus, not two. Microsoft says that if you install a compatible antivirus program from another company, Microsoft Defender Antivirus turns itself off automatically. So the suite you install is then the one protecting you.
- Keep it working. The ACSC’s advice is that if you use different anti-malware software, make sure it is actively protecting you. If a trial that came with the computer has run out and you’d rather not pay, Microsoft says that once the other app is uninstalled, Defender turns back on automatically. Afterwards, check the Home page in Windows Security shows green.
Download any suite only from its maker’s own website or the app store. The ACSC says the same of password managers: use one from a trusted and reputable source.
A pop-up says the computer has a virus. Is it real?
If it shows a phone number or tells you to ring someone, it’s a scam. Microsoft says its error and warning messages never include a phone number, and that it doesn’t send unsolicited emails or make unsolicited phone calls. Microsoft says these pop-ups often won’t go away and can fill the whole screen, to make the web browser look locked.
Scamwatch’s advice is not to click a warning that pops up, and to go to the program it names directly to check. On Windows, that means leaving the pop-up alone and opening Windows Security yourself from the Start menu to run a scan.
If the computer is just slow, that isn’t always a virus either. Is it the computer or the internet? sorts out which in a few minutes, and if it’s the connection, an internet technician who tests the line and the modem is the visit for that.
When to call us, and when you don’t need to
You don’t need anyone if Windows Security shows green, Windows Update or Software Update says you’re up to date, and your files are backed up. That is ten minutes with the steps above, and it’s yours to do.
Call us when:
- Something on the Home page stays yellow or red and you’re not sure what it wants.
- A trial or a second antivirus keeps nagging, and you’d like it sorted with you watching.
- There’s no backup yet, and you’d like one set up and tested.
- A pop-up or a caller got you worried, and you want the computer checked after the bank knows.
A home tech support visit checks the protection is on, switches on the updates and backups, and shows you where everything is. You type your own passwords; we never sign in as you. We come to the house and don’t do remote support, and a visit is setup and help, with no hardware repair or data recovery.
Not sure it’s worth a visit? Send us a message, or ring 02 9188 1577.
Frequently asked questions
Is Windows Defender enough?
Microsoft builds Microsoft Defender Antivirus into Windows, as part of the Windows Security app, and it scans what you open and download from the moment the computer starts. Australia's cyber security centre advises checking its real-time protection is on, and if you use other antivirus, making sure that one is actively protecting you. Paying for more is your choice. Updates, a backup and good passwords matter as much.
Do I need antivirus on a Mac?
Apple builds antivirus technology called XProtect into macOS, and updates it automatically. Gatekeeper checks apps before they open, and Apple says the App Store is the safest place to get them. Apple describes these as working together to protect against viruses and malware. Keep macOS up to date, turn on Install Security Responses and system files, and back up with Time Machine.
How do I check Windows Defender is on?
Select Start, type Windows Security and open it. On its Home page, green means Microsoft sees nothing to do, yellow means a recommendation, and red needs your attention now. Then select Virus & threat protection, then Manage settings, and check Real-time protection is On. Under Protection updates, select Check for updates. If another antivirus app is installed and turned on, Microsoft says Defender turns itself off.
Is a virus warning pop-up on my computer real?
Treat it as fake if it gives a phone number or tells you to ring someone. Microsoft says its error and warning messages never include a phone number. Don't click it or ring it. Open Windows Security yourself from the Start menu and run a scan. If you already rang the number or let someone onto the computer, follow these steps for after a scam.
Need this fixed rather than explained?
This is written from the field. When the fault needs a technician on site, this is where to go next.