This article describes an antimalware platform update package for Microsoft Defender for the following operating systems:
- Windows 10 (Enterprise, Pro, and Home editions)
- Windows Server 2019
- Windows Server 2016
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: 4.18.2005.5
Note Version 4.18.2001.10 is re-released to prevent supersedence. For more information, see Manage Windows Defender Antivirus updates and apply baselines.
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.
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:
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.
You do not have to restart the system after you install this update.
Note Platform update 4.18.2001.10 might require a restart.
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