How to Update Microsoft Defender and Run a Quick Scan in One Go

The Microsoft Defender command-line utility MpCmdRun.exe is mostly used to schedule scans and update the definitions. The MpCmdRun.exe command usage info can be obtained by running MpCmdRun.exe with “/?” or without any parameter.

However, it doesn’t mention a useful switch that updates Defender signatures and runs a Quick Scan at once.

MpCmdRun.exe — Signature Update & Quick Scan

To update the definitions and run a Quick Scan in one go, use the switch SignatureUpdateAndQuickScan

"C:\Program Files\Windows Defender\MpCmdRun.exe" /SignatureUpdateAndQuickScan

windows defender command-line switches

… and the event (1001) is written to Microsoft-Windows-Windows Defender/Operational event log.

windows defender scan event log

Other MpCmdRun.exe command-line switches

Here are the other commonly used MpCmdRun.exe command-line switches:

Run a Quick Scan

"C:\Program Files\Windows Defender\MpCmdRun.exe" -Scan -ScanType 1

Run a Full Scan

"C:\Program Files\Windows Defender\MpCmdRun.exe" -Scan -ScanType 2

Update the Definitions

"C:\Program Files\Windows Defender\MpCmdRun.exe" -SignatureUpdate

To see the complete list of arguments, open a Command Prompt window and type:

"C:\Program Files\Windows Defender\MpCmdRun.exe"

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Ramesh Srinivasan is passionate about Microsoft technologies and he has been a consecutive ten-time recipient of the Microsoft Most Valuable Professional award in the Windows Shell/Desktop Experience category, from 2003 to 2012. He loves to troubleshoot and write about Windows. Ramesh founded in 2005.

3 thoughts on “How to Update Microsoft Defender and Run a Quick Scan in One Go”

  1. for others who have the error “some explanation in red” you may need to check the folder path.

    MpCmdRun.exe may be located in
    C:\ProgramData\Microsoft\Windows Defender\Platform\4.18.XXXXX.X-0


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