How to Scan a File or Folder with Windows Defender on Windows 10

To scan a file or folder on Windows 10, the fastest method is to right-click it in File Explorer and choose Scan with Microsoft Defender. Windows Security will check the selected item and show the result. You can also use a Custom scan from the Windows Security app when you want to scan a whole folder, USB drive, or another location.

Important: Windows 10 reached end of support on October 14, 2025. These scanning tools can still work on a Windows 10 PC, but antivirus protection is not a replacement for operating-system security updates. Microsoft recommends moving to Windows 11 when possible or using an eligible Windows 10 Extended Security Updates option. See Microsoft's Windows 10 end-of-support guidance.

Scan a file or folder from File Explorer

This is the best option when you downloaded one file, received an attachment, copied something from a USB drive, or simply want to check a specific folder before opening its contents.

1. Open File Explorer and browse to the file or folder you want to check. Select the item, but do not open or run it if you are scanning it because you are unsure whether it is safe.

2. Right-click the item, then select Scan with Microsoft Defender. On Windows 10 this normally appears directly in the classic context menu. Microsoft's current support page covers the same on-demand scan feature for Windows 10 and Windows 11: Scan an item with Windows Security.

3. Wait for the scan to finish. Windows Security shows whether it found a threat. If the result is clean, you can close Windows Security. If Defender detects something, review the recommended action before using the file.

Run a Custom scan from Windows Security

A Custom scan is useful when the context-menu command is inconvenient or when you want to check an entire folder or removable drive. Microsoft describes a Custom scan as an on-demand scan of files and folders you specify.

1. Open Start, search for Windows Security, open it, and select Virus & threat protection.

2. Select Scan options.
3. Choose Custom scan, then select Scan now.

4. In the folder picker, select the folder or drive you want to scan, then choose Select Folder. The scan starts immediately.

5. When the scan finishes, review the result in Windows Security. You can also open Protection history to review detections and actions Defender has taken.

Which Microsoft Defender scan should you use?

Microsoft's Virus & threat protection documentation explains the available scan types. For routine protection, keep Real-time protection enabled. Defender monitors files and programs as they are accessed or executed, while manual scans are useful when you want an immediate second check.

If “Scan with Microsoft Defender” is missing

Open Windows Security > Virus & threat protection and check which antivirus provider is active. If you use a non-Microsoft antivirus product, Microsoft Defender Antivirus can switch to disabled mode automatically, so its File Explorer scan command may not be available. Do not disable your active antivirus just to make the Defender menu item appear.

If Defender finds a threat

Do not open the file. Open Protection history and review the detection. Defender may quarantine or block the item, or it may ask you to choose an action. Only use Allow on device when you are confident the detection is a false positive; allowing a real threat can put the device and your data at risk. Microsoft notes that Protection history keeps events for two weeks, so review important detections promptly.

The key point is simple: for a single file or folder, use the File Explorer Scan with Microsoft Defender command. Use a Custom scan when you need to target a larger location. There is no need to turn off real-time protection before running either type of scan.