Mac Security — Complete Guide for UK Users
There is a persistent myth that Macs do not get viruses. They do. Mac-specific malware is increasing as Apple devices become more common in UK households and businesses. The good news: macOS includes powerful security tools built in — most of which simply need to be switched on. This guide covers every step, using only free tools.
The real risk
The biggest threats to Mac users are not traditional viruses — they are phishing attacks, fake software downloads, and unencrypted data on stolen devices. All three are addressed in this guide.
Step 1 — Enable FileVault Disk Encryption
FileVault encrypts your entire hard drive. If your Mac is stolen, the thief cannot access any of your files without your password. It's free, built into every Mac, and has no noticeable performance impact on modern hardware.
How to do it
- 1Open System Settings (or System Preferences on older macOS) → Privacy & Security
- 2Scroll to FileVault
- 3Click Turn On FileVault
- 4Choose to allow your iCloud account or a recovery key to unlock the disk
- 5Save your recovery key somewhere safe — printed or in a password manager
Step 2 — Enable Automatic macOS and App Updates
macOS updates fix security vulnerabilities. Many Mac users skip updates because they are inconvenient — but an unpatched Mac is a vulnerable Mac.
How to do it
- 1Open System Settings → General → Software Update
- 2Enable Automatic updates
- 3Click the information (ⓘ) icon and turn on all four options: Check for updates, Download new updates, Install macOS updates, Install app updates from the App Store
Step 3 — Check Your Firewall Settings
macOS includes a built-in firewall that blocks unauthorised incoming connections. It is often off by default — check it is active.
How to do it
- 1Open System Settings → Network → Firewall
- 2If the firewall is off, click the toggle to turn it on
- 3Click Options to see and control which apps are allowed to accept incoming connections
Step 4 — Review App Permissions
Apps on your Mac can request access to your camera, microphone, location, and contacts. Review what has been granted and revoke anything that is not necessary.
How to do it
- 1Open System Settings → Privacy & Security
- 2Work through each category: Camera, Microphone, Location Services, Contacts, Calendar
- 3Revoke access for any app that does not genuinely need it
- 4Pay particular attention to browser extensions — these often have broad access
Step 5 — Set a Screen Lock and Strong Login Password
Your Mac should require a password or Touch ID to wake from sleep. Set the screen to lock after 5 minutes of inactivity.
How to do it
- 1Open System Settings → Lock Screen
- 2Set Require password after screen saver begins or display is turned off to Immediately or After 5 minutes
- 3Ensure your login password is a strong, unique passphrase
- 4Enable Touch ID if your Mac supports it (System Settings → Touch ID & Password)
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Frequently asked questions
Are Macs safe from viruses?
No. Macs are targeted less frequently than Windows PCs because they represent a smaller share of the market, but Mac-specific malware exists and is increasing. The steps in this guide significantly reduce your risk.
Do I need antivirus software on a Mac?
macOS includes built-in security (XProtect and Gatekeeper) that handles most common threats. For extra peace of mind, Malwarebytes for Mac has a free version that is well regarded. You don't need to pay for antivirus if you follow the steps in this guide.
How do I know if my Mac has been hacked?
Signs include: unusual slowness, unfamiliar apps appearing in your Dock or Applications folder, your browser redirecting to unexpected pages, or contacts receiving messages from your accounts that you did not send. Run Activity Monitor to check for unexpected processes consuming resources.