Microsoft Defender Antivirus compatibility

Applies to:

Overview

Microsoft Defender Antivirus is automatically enabled and installed on endpoints and devices that are running Windows 10. But what happens when another antivirus/antimalware solution is used? It depends on whether you're using Microsoft Defender ATP together with your antivirus protection.

  • If your organization's endpoints and devices are protected with a non-Microsoft antivirus/antimalware solution, and Microsoft Defender ATP is not used, then Microsoft Defender Antivirus automatically goes into disabled mode.
  • If your organization is using Microsoft Defender Advanced Threat Protection (Microsoft Defender ATP) together with a non-Microsoft antivirus/antimalware solution, then Microsoft Defender Antivirus automatically goes into passive mode. (Real-time protection and threats are not remediated by Microsoft Defender Antivirus.)
  • If your organization is using Microsoft Defender ATP together with a non-Microsoft antivirus/antimalware solution, and you have EDR in block mode (currently in private preview) enabled, then Microsoft Defender Antivirus runs in the background and blocks/remediates malicious items that are detected, such as during a post-breach attack.

Antivirus and Microsoft Defender ATP

The following table summarizes what happens with Microsoft Defender Antivirus when third-party antivirus products are used together or without Microsoft Defender ATP.

Windows version Antimalware protection offered by Organization enrolled in Microsoft Defender ATP Microsoft Defender Antivirus state
Windows 10 A third-party product that is not offered or developed by Microsoft Yes Passive mode
Windows 10 A third-party product that is not offered or developed by Microsoft No Automatic disabled mode
Windows 10 Microsoft Defender Antivirus Yes Active mode
Windows 10 Microsoft Defender Antivirus No Active mode
Windows Server 2016 or 2019 A third-party product that is not offered or developed by Microsoft Yes Active mode[1]
Windows Server 2016 or 2019 A third-party product that is not offered or developed by Microsoft No Active mode[1]
Windows Server 2016 or 2019 Microsoft Defender Antivirus Yes Active mode
Windows Server 2016 or 2019 Microsoft Defender Antivirus No Active mode

(1) On Windows Server 2016 or 2019, Microsoft Defender Antivirus will not enter passive or disabled mode if you have also installed a third-party antivirus product. If you install a third-party antivirus product, you should consider uninstalling Microsoft Defender Antivirus on Windows Server 2016 or 2019 to prevent problems caused by having multiple antivirus products installed on a machine.

If you are Using Windows Server, version 1803 and Windows 2019, you can enable passive mode by setting this registry key:

  • Path: HKLM\SOFTWARE\Policies\Microsoft\Windows Advanced Threat Protection
  • Name: ForceDefenderPassiveMode
  • Type: REG_DWORD
  • Value: 1

See Microsoft Defender Antivirus on Windows Server 2016 and 2019 for key differences and management options for Windows Server installations.

Important

Microsoft Defender Antivirus is only available on endpoints running Windows 10, Windows Server 2016, and Windows Server 2019.

In Windows 8.1 and Windows Server 2012, enterprise-level endpoint antivirus protection is offered as System Center Endpoint Protection, which is managed through Microsoft Endpoint Configuration Manager.

Windows Defender is also offered for consumer devices on Windows 8.1 and Windows Server 2012, although it does not provide enterprise-level management (or an interface on Windows Server 2012 Server Core installations).

Functionality and features available in each state

The following table summarizes the functionality and features that are available in each state:

State Real-time protection and cloud-delivered protection Limited periodic scanning availability File scanning and detection information Threat remediation Security intelligence updates
Active mode

Yes No Yes Yes Yes
Passive mode No No Yes No Yes
EDR in block mode enabled No No Yes Yes Yes
Automatic disabled mode No Yes No No No
  • In Active mode, Microsoft Defender Antivirus is used as the antivirus app on the machine. All configuration made with Configuration Manager, Group Policy, Intune, or other management products will apply. Files are scanned and threats remediated, and detection information are reported in your configuration tool (such as Configuration Manager or the Microsoft Defender Antivirus app on the machine itself).
  • In Passive mode, Microsoft Defender Antivirus is not used as the antivirus app, and threats are not remediated by Microsoft Defender Antivirus. Files are scanned and reports are provided for threat detections which are shared with the Microsoft Defender ATP service.
  • When EDR in block mode (currently in private preview) is turned on, Microsoft Defender Antivirus is not used as the primary antivirus solution, but can still detect and remediate malicious items.
  • In Automatic disabled mode, Microsoft Defender Antivirus is not used as the antivirus app. Files are not scanned and threats are not remediated.

Keep the following points in mind

If you are enrolled in Microsoft Defender ATP and you are using a third party antimalware product then passive mode is enabled because the service requires common information sharing from the Microsoft Defender Antivirus service in order to properly monitor your devices and network for intrusion attempts and attacks.

When Microsoft Defender Antivirus is automatic disabled, it can automatically re-enable if the protection offered by a third-party antivirus product expires or otherwise stops providing real-time protection from viruses, malware or other threats. This is to ensure antivirus protection is maintained on the endpoint. It also allows you to enable limited periodic scanning, which uses the Microsoft Defender Antivirus engine to periodically check for threats in addition to your main antivirus app.

In passive mode, you can still manage updates for Microsoft Defender Antivirus; however, you can't move Microsoft Defender Antivirus into the normal active mode if your endpoints have an up-to-date third-party product providing real-time protection from malware.

If you uninstall the other product, and choose to use Microsoft Defender Antivirus to provide protection to your endpoints, Microsoft Defender Antivirus will automatically return to its normal active mode.

Warning

You should not attempt to disable, stop, or modify any of the associated services used by Microsoft Defender Antivirus, Microsoft Defender ATP, or the Windows Security app. This includes the wscsvc, SecurityHealthService, MsSense, Sense, WinDefend, or MsMpEng services and process. Manually modifying these services can cause severe instability on your endpoints and open your network to infections and attacks. It can also cause problems when using third-party antivirus apps and how their information is displayed in the Windows Security app.