How to Remove Virus From Computer (Mac & PC Guide)

Viruses are the menace that no computer user wants to deal with. But if your PC or Mac is acting strange, there’s a good chance one has already found its way in.

Viruses can affect your PC’s performance and spoof your personal data. Depending on the type of virus, they can also steal passwords, corrupt files, or even lock you out of your own system. Fortunately, most viruses can be removed and future ones prevented with the right measures.

Below, I’ll walk you through the symptoms of a computer virus and the steps you can take to remove it from your Mac or Windows PC.

Signs Your Computer Has a Virus

A virus can make your computer behave differently as it infects different apps and files. Here are the typical symptoms of virus infection:

• Slow performance: Malware often consumes system resources to perform tasks in the background. If your computer is working painfully slow, know that malware may have hogged the CPU and RAM of your PC.
• Disabled security software: Malicious software often attempts to disable your antivirus, firewall, or OS updates to prevent detection. If your security programs are turned off and cannot be re-enabled, there’s a chance that your computer has contracted a virus.
• Missing or corrupted files: Viruses can corrupt and delete files as well as move them to hidden locations. If you cannot open specific documents, or if your files have completely vanished, a virus may be the cause.
• Unfamiliar apps: Another telltale sign is the appearance of apps that you do not remember downloading. Viruses often encrypt and hide behind legitimate files to get through the vetting process.
• Bogus pop-ups: Some viruses trick you into downloading them by showing fake warnings that say your device is infected. If you see a pop-up saying “Warning: Your device is at risk” on your Mac or PC, run a security scan because the source is likely to be on your system.

How to Remove a Virus From a Windows PC

Windows computers have a higher chance of contracting a virus than PCs running other operating systems. If you suspect that your Windows PC has been infected, follow these steps to remove the virus: 

Change Your Passwords

Assume any passwords you typed while infected were compromised. Change all your critical passwords, including those for banking, email, and social media. If you’re using a password manager, leverage it to generate new, complex passwords for your accounts. 

Enter Safe Mode and Delete Temporary Files

Restart your PC and hold the Shift key while choosing Power > Restart from the Start menu. Then go to Troubleshoot> Advanced options > Startup Settings > Restart, and press F4 or 4 to enter Safe Mode.

Once in Safe Mode, type Disk Cleanup in the search bar and choose the C: drive. In this drive, look for Temporary files and remove them from your system. Doing this can speed up virus scanning and eliminate viruses hiding in plain sight.

Do a Full Scan

Open your antivirus software or  and run a full system scan. In Windows Security, navigate to Virus & threat protection, click Scan options, and choose Full Scan. After the scan completes, let the antivirus quarantine or delete any malicious files. 

Then restart your computer and see if the virus symptoms are still there. If any signs show up, use Microsoft Defender Offline to scan for the virus. This tool scans Windows before it fully loads, allowing it to detect rootkits and other programs that hide from conventional scanners.

Uninstall Suspicious Apps

See if there is any unrecognizable application or software on your computer and delete it. Head to Control Panel > Programs and click Uninstall for removal. 

Reset Browser Settings

Malware can modify browser settings and install malicious extensions without you knowing. To reduce the risk of browser hijacks, reset your browser’s settings to their original defaults.

• On Chrome, go to Settings > Reset settings > Restore settings to bring back the defaults. 
• On Firefox, go to Menu > Help > More troubleshooting information > Refresh Firefox.
• On Edge, go to Settings > Reset settings > Restore settings to their original state. 

How to Remove a Virus From a Mac

Although Macs come with robust threat detection and built-in security features, they aren’t fully immune to viruses. Here are the steps to take should you experience any symptoms of virus infection.  

Disconnect From Internet 

Before anything else, unplug the Ethernet cable and disconnect your Mac from Wi-Fi to prevent the virus from spreading or communicating with its server.

Enter Safe Mode

On an Intel Mac, restart the computer and immediately hold down the Shift key until the login window shows up. On an Apple Silicon M1, M2, or M3 Mac, shut down the computer and press and hold the power button until you see “Loading startup options.” Then choose your disk, press and hold Shift, and select Continue in Safe Mode. 

Run a Virus Scan

Since the virus may be residing somewhere deep, perform a scan using a reputable Mac antivirus like Malwarebytes or Bitdefender for Mac. Antivirus is recommended for detecting and removing hidden malware and PUPs (potentially unwanted programs) from your computer. 

Remove Login Items

While you’re deleting apps, also check System Settings > General Login Items (or Users & Groups) on older macOS for any malicious applications and remove them. This will prevent the virus from booting as your Mac starts its system and opens relevant apps automatically. 

Delete Suspicious Apps 

Open the Applications folder and see if you can spot any program that you do not remember installing. Apps that appeared around the time of infection are probably carrying executable code with them. Delete any such apps by clicking on them and dragging them to the Trash folder.

Check Activity Monitor

Go to Applications > Utilities and open Activity Monitor to check for malicious processes. Flag any process that you feel is hogging memory or CPU. Malware may use names like MacSecurity and MacDefender to skip detection, so be wary of any such items appearing in the Activity Monitor. You can delete a process by double-clicking on it and choosing the X button to force-quit the item. 

Tips to Prevent Future Computer Viruses

After removing the virus, you can take a few steps to harden your PC’s security.

• Update all software: Regularly update your browser, applications, and operating system to patch security vulnerabilities. 
• Activate firewall:  Enable the built-in firewall on your computer to prevent malicious programs from entering your system and block existing viruses from communicating with external servers.
• Be cautious on public Wi-Fi: Do not access sensitive information on untrusted Wi-Fi networks. Or, use a VPN to encrypt your data before you open any banking apps or log into your work account.
• Browse securely: Avoid interacting with sites that don’t use HTTPS and use ad blockers to stop malvertising (the constant appearance of malicious ads).
• Download from official sources: Only download apps from official, trusted sources like Apple’s App Store to avoid bundled malware. That same rule is especially important on iPhones, where fake apps, malicious websites, and unsafe configuration profiles are among the most common ways malware gets onto a device in the first place.
• Turn off unused services: Disable Bluetooth, file sharing, and remote desktop services when they’re not in use.
• Restrict privileges: Create a standard user account for routine tasks to prevent malware from gaining full control via administrator.

Frequently Asked Questions