To check which microsoft antivirus is installed

Windows Security is the built-in management app, while Microsoft Defender Antivirus is the antivirus engine inside it; you normally open Windows Security to check and run Defender. Both are included with Windows 10 and Windows 11. If another antivirus is active, Microsoft Defender Antivirus normally turns off automatically.^1^

Check which antivirus is active

1. Open Start.
2. Type Windows Security, then open it.
3. Select Virus & threat protection.
4. Under Who’s protecting me?, select Manage providers.
5. Look under Antivirus:
   • Microsoft Defender Antivirus is turned on means Defender is your active antivirus.
   • If another product is named, that product is the active antivirus provider.

This provider page is more reliable than checking whether an application icon exists.^2^

Open Defender and run a scan

From Windows Security → Virus & threat protection:

• Select Quick scan for the common threat locations.
• Select Scan options to choose:
  • Full scan — scans every file and program.
  • Custom scan — scans selected folders.
  • Microsoft Defender Antivirus (offline scan) — restarts the computer and scans outside normal Windows; save open files first.

You can also right-click a file or folder in File Explorer and select Scan with Microsoft Defender. On Windows 11, select Show more options first if that command is hidden.^3^

Check and run Defender with PowerShell

Open Start, search for PowerShell, and open Windows PowerShell. Run:

# Display Defender's operating mode and protection status
Get-MpComputerStatus |
    Select-Object AMRunningMode, AntivirusEnabled,
                  RealTimeProtectionEnabled

# Start a quick scan
Start-MpScan -ScanType QuickScan

Interpret AMRunningMode as follows:

• Normal — Defender is the active antivirus.
• Passive or SxS Passive Mode — Defender is present but is not the primary antivirus.
• EDR Block Mode — a Microsoft Defender for Endpoint configuration is active.

Get-MpComputerStatus checks protection status, while Start-MpScan triggers a scan.^4^

About the separate “Microsoft Defender” app

If Microsoft Defender also appears in Start, it may be the separate dashboard included with certain Microsoft 365 subscriptions. It is not the same thing as the built-in antivirus engine. For checking this PC’s antivirus provider or running a local scan, use Windows Security → Virus & threat protection.

References

1. Windows Security App Overview | Microsoft Support
2. Microsoft Defender Antivirus in Windows Overview
3. Stay protected with the Windows Security app | Microsoft Support
4. Use PowerShell cmdlets to configure and manage Microsoft Defender Antivirus