How to Remove a Virus or Malware?
Common Windows and Mac Malware Problems — and What to Do
Have you noticed strange pop-ups, unwanted advertisements, browser redirects, or other unusual behaviour on your Windows PC or Mac?
Your computer may be affected by malware, potentially unwanted software, a browser hijacker, or another security threat. However, not every unusual computer problem is caused by a virus.
The symptoms you see can provide useful clues about what is happening.
In this guide, we explain the most common signs of malware, what you can check safely, and when professional malware removal may be needed.
What Does a "Malware Problem" Actually Mean?
Unexpected pop-ups and advertisements
Unexpected pop-ups and advertisements
Ads or security warnings appear even when you are not visiting a website? This may be caused by unwanted software or browser notifications.
Your browser keeps redirecting
Your browser keeps redirecting
Websites open that you did not request, or your homepage and search engine keep changing? A browser extension or unwanted software may be responsible.
Unknown programs or extensions appear
Unknown programs or extensions appear
You find applications, browser extensions or other software that you do not remember installing? Check them carefully before removing anything.
The computer suddenly becomes very slow
The computer suddenly becomes very slow
Malware can consume CPU, memory, storage or network resources. However, a slow computer does not automatically mean it has a virus.
Antivirus keeps detecting the same threat
Antivirus keeps detecting the same threat
The same threat keeps returning after a restart or removal attempt? This may indicate that another component is reinstalling or restoring the unwanted software.
Suspicious security warnings keep appearing
Suspicious security warnings keep appearing
A message says your computer is infected and tells you to call a number or install software? Be careful — the warning itself may be part of a technical-support scam.
Your browser settings keep changing
Your browser settings keep changing
Search settings, homepage, new-tab page or notification permissions change without you intending to do so? Unwanted software or extensions may be involved.
Common Causes of Virus and Malware Problems
- Malicious software — Viruses, trojans, spyware, ransomware and other types of malware can affect a computer in different ways.
- Malicious websites or downloads — Malware can be delivered through deceptive websites, downloads or files.
- Fake software updates — A fake browser or software update may actually install unwanted software.
- Suspicious email attachments or links — Opening a malicious attachment or following a fraudulent link can lead to a security problem.
- Unwanted browser extensions — Some extensions can change search settings, display advertisements or track browsing.
- Bundled software — Some installers include additional programs that users did not intend to install.
- Outdated software — Security vulnerabilities in operating systems, browsers and applications can increase risk.
- Compromised accounts — Sometimes the problem is not malware on the computer itself, but a compromised email, browser or online account.
What to Do When You Suspect Malware
On Windows
Including Windows 10 and Windows 11, whether running on a Desktop PC, Laptop, All-in-one Computer or Tablet.
Try these steps before considering a major repair:
1. Protect your important data- If you can safely access your files, make sure important documents and photos are backed up.
- If ransomware or suspicious encryption is suspected, disconnect the computer from the network and avoid unnecessary changes.
- Open Windows Security → Virus & threat protection.
- Start with a Quick scan and use a Full scan if needed.
- If a threat keeps returning, Microsoft Defender Offline can scan outside the normal Windows environment.
- Review recently installed programs and remove software you can confidently identify as unwanted.
- Check browser extensions and remove ones you do not recognise or need.
- If the same detection or suspicious behaviour returns after restarting, further investigation may be required.
On a Mac
Including recent macOS versions, whether running on a MacBook, iMac, Mac mini, Mac Studio or other Mac computer.
Try these steps before considering a major repair:
1. Don't assume a Mac cannot get malware- macOS includes built-in security protections, but malicious and unwanted software can still affect a Mac.
- Look for applications you do not recognise or did not intentionally install.
- Be particularly careful with software downloaded from unfamiliar websites.
- Review Safari, Chrome, Firefox or other browser extensions.
- Suspicious browser notifications can sometimes look like genuine antivirus warnings.
- Use a reputable security product when a malware scan is appropriate.
- If you are unsure what should be removed, avoid deleting system files or applications at random.
When Should You Stop Troubleshooting?
- The hard drive (or SSD) is not detected
- The drive is making unusual noises (risk of permanent data loss)
- The computer repeatedly restarts
- Windows reports that the drive cannot be repaired
- macOS Disk Utility cannot see the internal drive
- The computer has recently suffered a drop or liquid spill
- Important files are stored on the computer
- You have already tried Startup Repair or Recovery without success
- You are unsure whether a repair will erase your data
Common questions
Does a slow computer always mean it has a virus?
Does Windows Defender remove viruses?
Can a Mac get viruses or malware?
Should I install several antivirus programs?
Should I reinstall Windows or macOS to remove malware?
Can you remove malware without deleting my files?
Don't Trust Every "Virus Warning"
Be careful when a website suddenly displays a message such as “Your computer is infected!” and tells you to install software or call a phone number.
Some of these warnings are designed to frighten you into downloading unwanted software or giving someone remote access to your computer.
Do not give an unknown person remote access to your computer or provide passwords, banking information or other sensitive information because of a pop-up warning.
If you are unsure whether a warning is genuine, close the browser and have the computer checked.