How To Run Windows Defender Scan On Windows 11: A Step-by-Step Guide

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Edgar Nicov

How-To

5 min. read

Published on October 25, 2025

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Windows Defender, now known as Microsoft Defender Antivirus, is your first line of defense against malware and other threats on your Windows 11 system. Keeping your system secure involves regularly scanning for potential problems. This guide will walk you through the various methods to initiate a Windows Defender scan, ensuring your computer remains protected.

Whether you prefer a quick check or a more thorough examination, Windows 11 provides several ways to run a scan. This step-by-step guide covers everything from the basic quick scan to custom scans targeting specific files or folders, giving you complete control over your system’s security.

How Do I Start a Windows Defender Scan on Windows 11?

Using the Windows Security App

The Windows Security app provides a user-friendly interface for managing your system’s security, including running Windows Defender scans.

Open the Windows Security app: Click the Start button, type “Windows Security,” and select the app from the search results.
Navigate to Virus & threat protection: In the Windows Security app, click on the “Virus & threat protection” icon.
Choose a scan option: You will see several scan options:

Quick scan: This performs a fast scan of the most common locations where threats are found. Click the “Quick scan” button to start.
Scan options: For more control, click “Scan options” to choose from:
Full scan: Scans every file on your system, which takes longer but is more thorough.
Custom scan: Allows you to select specific files or folders to scan.
Microsoft Defender Offline scan: Restarts your computer and performs a scan in an offline environment, which can detect more sophisticated malware.

Start the selected scan: After choosing your scan option, click the “Scan” button to begin.

Using the Context Menu (Right-Click)

This method is convenient for scanning specific files or folders directly.

Locate the file or folder: Find the file or folder you want to scan in File Explorer.
Right-click the item: Right-click on the file or folder.
Select “Scan with Microsoft Defender”: In the context menu that appears, select “Scan with Microsoft Defender.” This will immediately start a scan of the selected item.

Using Command Prompt

For advanced users, the Command Prompt offers a powerful way to initiate scans.

Open Command Prompt as administrator: Click the Start button, type “cmd,” right-click “Command Prompt,” and select “Run as administrator.”
Run the scan command: Type the following command and press Enter:

"%ProgramFiles%\Windows Defender\MpCmdRun.exe" -Scan -ScanType 1 (for a quick scan) or "%ProgramFiles%\Windows Defender\MpCmdRun.exe" -Scan -ScanType 2 (for a full scan)

Monitor the scan: The Command Prompt will display the progress and results of the scan.

Scheduling Scans

Regular scheduled scans ensure your system remains protected without manual intervention.

Open Task Scheduler: Click the Start button, type “Task Scheduler,” and select the app from the search results.
Create a basic task: In the Task Scheduler, click “Create Basic Task” in the right-hand pane.
Name the task: Give the task a name (e.g., “Windows Defender Scheduled Scan”) and click “Next.”
Set the trigger: Choose how often you want the scan to run (e.g., Daily, Weekly, Monthly) and click “Next.”
Configure the trigger details: Specify the exact time and day(s) for the scan and click “Next.”
Choose the action: Select “Start a program” and click “Next.”
Enter the program details: In the “Program/script” field, enter:

"%ProgramFiles%\Windows Defender\MpCmdRun.exe" In the “Add arguments” field, enter: -Scan -ScanType 2 (for a full scan)

Finish the task: Review the task details and click “Finish.”

Tips

Keep Windows Defender up to date with the latest virus definitions for optimal protection.
Run a full scan periodically, even if you have scheduled scans in place.
If you suspect a file is infected, use the context menu scan option for immediate action.
Review scan results regularly to address any detected threats.

Keeping Your System Safe

Regularly scanning with Windows Defender is crucial for maintaining a secure Windows 11 system. By following these steps, you can ensure your computer is protected from malware and other threats, contributing to a smoother and safer computing experience.

FAQ

How often should I run a Windows Defender scan? It’s recommended to run a quick scan daily and a full scan at least once a week.

Does a Windows Defender scan slow down my computer? A full scan can temporarily slow down your computer, so it’s best to run it when you’re not actively using your system. Quick scans have minimal impact.

Can Windows Defender remove viruses? Yes, Windows Defender can detect and remove many types of viruses and malware.

How do I update Windows Defender definitions? Windows Defender typically updates its definitions automatically. You can manually check for updates in the Windows Security app under “Virus & threat protection” and then “Virus & threat protection updates.”

What is Microsoft Defender Offline scan? Microsoft Defender Offline scan restarts your computer and performs a scan in an offline environment, which can detect more sophisticated malware that might be hidden while Windows is running.

Windows Defender Scan Types Compared

Feature	Quick Scan	Full Scan	Custom Scan	Microsoft Defender Offline Scan
Scope	Common locations for threats	Entire system (all files and programs)	Specific files or folders selected by user	Scans system offline before Windows starts
Time	Fast (minutes)	Slow (hours)	Varies depending on selection	Requires restart, can take moderate time
Thoroughness	Basic protection	Comprehensive protection	Targeted protection	Deepest level of protection
Best Used For	Daily checks, quick assessment	Regular maintenance, thorough assessment	Scanning suspicious files or folders	Detecting persistent or rootkit-level threats