Scan a suspicious item with Windows Security
Use File Explorer for an individual item and Windows Security scan options when you need a folder or broader system check.
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Setup and conditions
To check a downloaded file or folder, locate it in File Explorer, right-click it, choose Show more options, then select Scan with Microsoft Defender. Windows Security opens the Virus & threat protection area where you can review the result. You can select multiple items before opening the context menu. If the command is unavailable, use Windows Security’s Custom scan option to choose the containing folder.
A workflow to try
In Windows Security, open Virus & threat protection > Scan options to choose Quick, Full, Custom, or Microsoft Defender Offline scanning. Custom scanning fits a known folder or removable drive; a broader scan may be more appropriate when you suspect an infection but do not know where it is. Offline scanning restarts the PC, so save open work and schedule it when an interruption is acceptable.
Practitioner perspective
Windows How-To Expert Mauro Huculak’s Windows Central guide compares Windows 11 methods for manually scanning files and folders, including File Explorer and a Custom scan. A manual check is useful for a specific item, but it does not replace real-time protection or current security intelligence. Microsoft notes that a third-party antivirus product can cause Microsoft Defender Antivirus to be disabled. Check which protection is active in Windows Security and manage one configured product’s updates and results rather than assuming multiple scanners are simultaneously protecting the device.
Limits and checks
Microsoft’s item-scan instructions use Show more options to reach the command in Windows 11. If it still does not appear, check whether another antivirus is active; on a managed PC, ask IT whether policy hides the option. If a threat is detected, follow the quarantine or removal instructions and do not reopen the file. A clean result applies to the scan and scope that ran at that time; it is not proof that every possible threat is permanently absent.