Your device is constantly exposed to potential security threats. Fortunately, Microsoft Defender Antivirus comes built into Windows 11 and Windows 10, providing reliable protection without requiring any additional software.
Although Real-Time Protection continuously monitors your system, it may not detect every hidden threat instantly. That’s where a Microsoft Defender Full Virus Scan becomes useful. A full scan thoroughly checks your hard drive, installed applications, system files, startup items, and other locations where malware commonly hides.
In this guide, you’ll learn exactly how to run a Microsoft Defender Full Virus Scan on Windows 11 and Windows 10.
Microsoft Defender Full Virus Scan & Its Work
Microsoft Defender Antivirus is Microsoft’s built-in security solution designed to protect Windows computers from viruses, ransomware, spyware, Trojans, rootkits, and other malicious software.
A Full Virus Scan is much more comprehensive than a quick scan. Instead of checking only the most commonly infected locations, it carefully scans almost every accessible file and folder on your computer.
During the scan, Microsoft Defender checks your files against its continuously updated threat database. It also analyzes suspicious behavior, examines running processes, scans removable drives that are connected during the scan, and reviews important Windows system areas where malware often attempts to hide.
If Defender detects a threat, it immediately isolates the infected file by placing it into Quarantine. This prevents the malicious file from running while allowing you to review or permanently remove it later.
A Full Scan is especially recommended if your computer is running slower than usual, displaying unexpected pop-ups, behaving strangely, or after downloading files from unknown sources.
Run Microsoft Defender Full Virus Scan on Windows 11/10
To run a Microsoft Defender Full Virus Scan on Windows 11 or Windows 10, open Windows Security, select Virus & threat protection, click Scan options, choose Full scan, and then click Scan now. Microsoft Defender will begin scanning your entire computer for viruses, malware, spyware, ransomware, and other security threats. Depending on the number of files on your PC, the scan may take anywhere from several minutes to a few hours.
The following steps walk you through the entire process in order.
Step 1: Open Windows Security
The first step is opening the Windows Security application, which is the central dashboard for all Microsoft Defender security features.
Click the Start button on your taskbar and type Windows Security into the search box. When the application appears in the search results, click it to open.
Another easy way is to open Settings, select Privacy & Security in Windows 11 or Update & Security in Windows 10, and then choose Windows Security. Click Open Windows Security to launch the app.
Once the application opens, you’ll see several security categories including Virus & threat protection, Firewall & network protection, Device security, and App & browser control. This dashboard gives you a complete overview of your PC’s security status.
Step 2: Open Virus & Threat Protection
Inside Windows Security, locate the Virus & threat protection section.
Click this option to access all antivirus-related settings. This page displays your current protection status, recent scan history, protection updates, ransomware protection, and available scan options.
If your device is protected correctly, you’ll usually see a green checkmark indicating there are no current threats.
If Microsoft Defender has detected suspicious files previously, they’ll also appear on this page so you can review them.
Step 3: Open Scan Options
Under the Current threats section, click Scan options.
This screen lets you choose between different scanning methods depending on your needs.
You’ll typically see Quick Scan, Full Scan, Custom Scan, and Microsoft Defender Offline Scan.
Each scan serves a different purpose. While a Quick Scan focuses on common malware locations, a Full Scan checks almost every accessible file stored on your computer. Since you’re looking for the most thorough protection, you’ll want to select the Full Scan option.
Step 4: Select Full Scan
Click the radio button beside Full Scan.
Choosing this option tells Microsoft Defender to examine your entire system rather than limiting the scan to high-risk areas.
A Full Scan inspects installed applications, downloaded files, Windows system folders, startup programs, temporary files, user profiles, and many other locations where malicious software may hide.
If your PC contains a large amount of data, don’t worry if the estimated scan time seems long. This is completely normal because Defender is carefully analyzing thousands or even millions of files.
Step 5: Click Scan Now
After selecting Full Scan, click the Scan now button.
Microsoft Defender immediately begins scanning your computer.
You’ll notice a progress indicator showing the scan status along with the number of files that have already been checked.
During this process, it’s perfectly fine to continue using your computer. However, because the antivirus is reading a large number of files, your system may feel slightly slower than usual until the scan finishes.
If you’re working on something important, consider starting the scan before taking a lunch break or at the end of the day.
Step 6: Wait for the Scan to Finish
A Full Virus Scan can take anywhere from thirty minutes to several hours, depending on several factors.
The scan duration depends on your computer’s processor speed, the type of storage drive you have, the number of installed programs, and the amount of data stored on your system.
Modern computers equipped with SSD storage generally complete scans much faster than older systems using traditional hard drives.
Avoid turning off your computer during the scan because doing so interrupts the process before Defender finishes checking every file.
If your laptop is running on battery power, it’s a good idea to connect the charger before starting a lengthy scan.
Step 7: Review the Scan Results
Once the scan completes, Microsoft Defender displays the results automatically.
If no threats are found, you’ll see a confirmation that your device is clean.
If suspicious files are detected, Defender usually recommends appropriate actions such as Quarantine, Remove, or occasionally Allow if you’re certain the file is safe.
For most users, selecting Quarantine is the safest choice because it isolates the file without deleting it immediately. This allows you to review it later if necessary.
You can also open Protection History to see detailed information about recently detected threats and the actions Microsoft Defender has taken.
How to Update Microsoft Defender?
Running a Full Virus Scan is only part of keeping your computer secure.
Microsoft regularly releases new Security Intelligence Updates that allow Defender to recognize the latest malware threats.
Within Virus & threat protection, click Protection updates and then select Check for updates.
Installing the latest security definitions ensures that future scans can identify newly discovered viruses and other malicious software.
Keeping Windows Update enabled also helps Microsoft Defender receive the newest improvements automatically.
Should I Run Full Scans Regularly?
One full scan isn’t enough for long-term protection.
Although Real Time Protection continuously monitors your system, scheduling regular Full Virus Scans provides an additional layer of security.
Many users run a full scan once every week or every couple of weeks, especially if they frequently download files, install new software, connect USB drives, or browse unfamiliar websites.
Combining Real-Time Protection, updated virus definitions, and regular full scans gives your Windows computer much stronger protection against modern cyber threats.
FAQs
Does a Microsoft Defender Full Scan remove viruses automatically?
If Microsoft Defender detects malware, it usually recommends actions such as Quarantine or Remove. In many cases, Defender automatically isolates dangerous files to prevent them from causing further damage.
How long does a Microsoft Defender Full Virus Scan take?
The scan time varies depending on your hardware and the number of files stored on your computer. It may take anywhere from thirty minutes to several hours.
Can I use my computer during a Full Scan?
Yes. You can continue using your PC while the scan is running. However, you may notice slightly slower performance because Microsoft Defender is actively scanning files in the background.
Does Microsoft Defender scan external USB drives?
If an external drive is connected and accessible during a Full Scan, Microsoft Defender can examine files stored on that device as part of the scanning process.
What is the difference between Quick Scan and Full Scan?
A Quick Scan checks the areas of Windows that are most commonly targeted by malware. A Full Scan thoroughly examines nearly every accessible file and folder on your computer, making it much more comprehensive.
Should I install another antivirus if I already use Microsoft Defender?
For most home users, Microsoft Defender Antivirus provides strong protection when combined with regular Windows updates, safe browsing habits, and routine full scans. Installing multiple antivirus programs simultaneously is generally not recommended because they can interfere with each other.
Summary
Running a Microsoft Defender Full Virus Scan is one of the easiest and most effective ways to protect your Windows 11 or Windows 10 computer from malware, ransomware, spyware, and other security threats. Unlike a quick scan, a Full Scan examines your entire system, helping detect hidden threats that may otherwise go unnoticed.
The process is straightforward. Open Windows Security, go to Virus & threat protection, select Scan options, choose Full Scan, and click Scan now. After the scan finishes, review the results, follow Microsoft’s recommended actions if threats are detected, and keep Microsoft Defender updated with the latest security intelligence.
Making Full Virus Scans part of your regular maintenance routine, along with keeping Windows updated and practicing safe online habits, will help ensure your computer stays secure, performs better, and remains protected against both existing and emerging cyber threats.