What is MsMpEng.exe?

The .exe extension on a filename indicates an executable file. Executable files may, in some cases, harm your computer. Therefore, please read below to decide for yourself whether the MsMpEng.exe on your computer is a Trojan that you should remove, or whether it is a file belonging to the Windows operating system or to a trusted application.

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MsMpEng.exe file information

Windows Task Manager with MsMpEng
MsMpEng.exe process in Windows Task Manager

The process known as Service Executable or Antimalware Service Executable or AntiMalware Service Executable or Microsoft Antimalware

belongs to software Windows Defender or Microsoft Malware Protection or Microsoft Security Essentials or Microsoft Antimalware Service or Microsoft Windows Operating System or Windows Defender Service or Microsoft Antimalware or Microsoft Antimalware Package

by Microsoft (

Description: MsMpEng.exe is not essential for the Windows OS and causes relatively few problems. MsMpEng.exe is located in a subfolder of "C:\Program Files" or sometimes in a subfolder of C:\ or in a subfolder of Windows Temp folder. Known file sizes on Windows 8/7/XP are 13,592 bytes (33% of all occurrences), 14,032 bytes and 31 more variants. 
The program has no visible window. MsMpEng.exe is certified by a trustworthy company. MsMpEng.exe is not a Windows system file. You can uninstall this program in the Control Panel. Therefore the technical security rating is 21% dangerous, however you should also read the user reviews.
In case of problems with MsMpEng.exe, you may also do the following:

Recommended: Identify MsMpEng.exe related errors

Important: Some malware camouflages itself as MsMpEng.exe, particularly when located in the C:\Windows or C:\Windows\System32 folder. Therefore, you should check the MsMpEng.exe process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.


User Comments

In my case I would NOT call it dangerous but it is harmful in the respect that it consumes way too much of the computers resources like cpu time & memory.
Constant CPU hog. Not worth what little (very little) it does.
This is the built in Windows Defender by Microsoft or the Microsoft Security Essentials antivirus. It is safe.
eats my cpu like its candy, avoid this anti virus program at all costs,poor me
it started bogging down the cpu after i opened a file that was malicious (im guessing) i deleted the file and cleared the recycle bin and msmpeng went back to normal. so it would seem that whatever your doing when msmpeng starts to bog you comp down is the cause, not msmpeng itself. then again i only know the basics of computers so i might be wrong.
this will take up all you cpu making your computer useless find a way to get rid of it because it will make your pc unusable
more CPU usage thane any security software .
  Abu Joloud  
Windows Defender!!!!
More comments can be found here:
    (further information)

Rating chart

Summary: Average user rating of MsMpEng.exe: based on 168 votes with 9 reviews. 99 users think MsMpEng.exe is essential for Windows or an installed application. 11 users think it's probably harmless. 23 users think it's neither essential nor dangerous. 12 users suspect danger. 23 users think MsMpEng.exe is dangerous and recommend removing it. 15 users don't grade MsMpEng.exe ("not sure about it").

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Best practices for resolving MsMpEng issues

A clean and tidy computer is the key requirement for avoiding problems with MsMpEng. This means running a scan for malware, cleaning your hard drive using cleanmgr and sfc /scannow, uninstalling programs that you no longer need, checking for Autostart programs (using msconfig) and enabling Windows' Automatic Update. Always remember to perform periodic backups, or at least to set restore points.

Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off doing a repair of your installation, or in the case of Windows 8, executing the DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.

To help you analyze the MsMpEng.exe process on your computer, the following programs have proven to be helpful: Security Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. Malwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.

Other processes

MsMpEng.exe [all]