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Windows malware is still a big problem. That’s why Microsoft ships an antivirus named Microsoft Defender with Windows 10. It scans for malware in the background, but you can also perform a full-system scan with Defender.

First, open the Start menu and type “Windows Security.” Click on the “Windows Security” app icon that pops up.

Open Start and type Windows Security on Windows 10

In the sidebar, click “Virus & Threat Protection.”

It’s possible to do a quick scan from here by clicking the “Quick Scan” button. If you haven’t scanned recently, you might want to consider doing a deeper scan. In the area below the “Current Threats” heading, click “Scan Options.”

In the “Scan Options” menu, you will see a list of four different types of scans you can perform on your computer using Microsoft Defender.

  • Quick Scan: Scans folders in your system where threats are usually found, such as the Downloads and Windows folders. This usually only takes a few minutes to complete.
  • Full Scan: This scans every file on your computer and all running programs as well. The scan may take longer than an hour to complete.
  • Custom Scan: If you choose this option, Windows Security will ask you for a specific file or folder location that you’d like to scan.
  • Microsoft Defender Offline Scan: This option restarts your machine and scans system files and programs while they are not running, which is useful if a piece of malware is currently running and potentially interfering with the scan.

If you haven’t tried Defender before or if your computer is acting funny and you’re worried about an obvious threat, it’s best to start with a Full scan. Select the radio button beside “Full Scan” and click the “Scan Now” button.

A full-system scan will begin, and Windows Security will show a progress indicator bar.

Microsoft Defender Full Scan in Progress on Windows 10

When the scan is complete, you’ll see the results. If everything was okay, you’ll see a message that says “No Current Threats.”

No current threats in Microsoft Defender on Windows 10

However, if the scan did find some malware, you will see a message that says “Threats Found” and a list of the infected files just below.

To remove the threats, click the “Start Actions” button.

Threat Found in Microsoft Defender on Windows 10

After clicking “Start Actions,” Microsoft Defender will remove the threats automatically. If you’d like to see details on what threats were removed, look beneath the scan results and click “Protection History.”

Also, if Defender found a threat during a Quick or Full scan, it may be wise to choose “Microsoft Defender Offline Scan” on the Scan Options screen and run it immediately afterward just in case. Hopefully, everything will come out normal. Good luck, and stay safe!

RELATED: How to See What Malware Windows Defender Found on Your PC

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Benj Edwards is a former Associate Editor for How-To Geek. Now, he is an AI and Machine Learning Reporter for Ars Technica. For over 15 years, he has written about technology and tech history for sites such as The Atlantic, Fast Company, PCMag, PCWorld, Macworld, Ars Technica, and Wired. In 2005, he created Vintage Computing and Gaming, a blog devoted to tech history. He also created The Culture of Tech podcast and regularly contributes to the Retronauts retrogaming podcast.
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