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 Windows Operating System or Microsoft Antimalware Service or Microsoft Antimalware or Microsoft Antimalware Package or Microsoft Security Essentials Prerelease

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:\. Known file sizes on Windows 10/8/7/XP are 13,592 bytes (30% of all occurrences), 14,032 bytes and 44 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.

Uninstalling this variant: 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

Windows Defender
Takes 100% of my disk space while im playing games.
MSmpeNG key found in Registry: "HKCU\SW\MS\Win\Current Version\RUN" pointing to "C:\Users\ username \AppData\Romaing\svc-xorl.exe" found by Malwarebytes as "Rogue.FakeAV"
Resource hog, but not spyware or virus... safe to kill it if you don't plan on downloading any viruses.
AVG found the Trojan Small.FHT in MsMpEng.exe on my recently downloaded version of Security Essentials. I had to uninstall Security Essentials to remove the Trojan.
This is Security Essentials - It is important. It is scanning new or updated files real time searching for Malware. If it is using a lot of CPU, then you have another problem that needs to be investigated.
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.
More comments can be found here:
    (further information)

Rating chart

Summary: Average user rating of MsMpEng.exe: based on 175 votes with 9 reviews. 100 users think MsMpEng.exe is essential for Windows or an installed application. 13 users think it's probably harmless. 24 users think it's neither essential nor dangerous. 14 users suspect danger. 24 users think MsMpEng.exe is dangerous and recommend removing it. 16 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 repairing of your installation or, for Windows 8 and later versions, 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]