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This article describes an antimalware platform update package for Microsoft Defender for the following operating systems:

  • Windows Server 2022

  • Windows 11

  • Windows 10 (Enterprise, Pro, and Home editions)

  • Windows Server 2019

  • Windows Server 2016

Version information

Note: After a new platform version is released, support for older versions (N-2) will reduce to technical support only. Platform versions older than N-2 will no longer be supported. See Manage Windows Defender Antivirus updates and apply baselines for details.

This update changes the antimalware client version.

  • New version: 4.18.2211.5

How to find the client version information

  • Windows 10, version 1709 and later versions

    Open the Microsoft Defender Security Center app, select the Settings icon, and then select About. The version number is listed under Antimalware Client Version.

  • Windows 10, version 1607, version 1703, and later versions

    Open the Microsoft Defender app, select Help, and then select About. The version number is listed under Antimalware Client Version.

Package information

The package name is listed as Update for Microsoft Defender antimalware platform. The package size is approximately 2-3 MB. 

Known issues in this update

  • New file path

    Because of a change in the file path location in the update, many downloads are blocked when AppLocker is enabled.

    To work around this issue, open Group Policy, and then change the setting to Allow for the following path:

    %OSDrive%\ProgramData\Microsoft\Windows Defender\Platform\*

Update information

This package includes monthly updates and fixes to the Microsoft Defender antimalware platform that is used by Microsoft Defender Antivirus in Windows 10.

Monthly updates are installed in addition to major Windows 10 releases. Both types of updates should be installed to ensure continued protection against malware and other threats.

For more information about the product versions and about how the updates work and how you can configure and manage them, see the Manage Windows Defender Antivirus updates and apply baselines topic.

File location changes

This update makes the following binary location changes.

Affected component

Old location

New location

Windows Defender Antivirus service (MsMpEng.exe)

Network Realtime Inspection service (NisSrv.exe)

%ProgramFiles%\Windows Defender

%ProgramData%\Microsoft\Windows Defender\Platform\<Version>

Windows Defender Antivirus drivers



All third-party applications that have references to these binaries must be updated to the new locations.

How to obtain this update

This update is available from Microsoft Update and WSUS. 

Restart requirement

You do not have to restart the system after you install this update.

How to roll back this update

To roll back this update, use the appropriate method:

  • To roll back this update to the previous version, run the following command:

    "%programdata%\microsoft\windows defender\platform\<version>\mpcmdrun.exe" -revertplatform

  • To roll back this update to the Inbox CAMP version, run the following command:

    "%programfiles%\Windows Defender\MpCmdRun.exe" -resetplatform


Learn about the terminology that Microsoft uses to describe software updates.

Third-party information disclaimer

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.

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