what does MsMpEng.exe actually do???

All,

I'm looking at some horrendous performance issues with our Windows 10 environment. Whilst the estate is old and low on resources in a lot of cases I don't think Windows 10 is helping matters. I'm using the usual tools (procmon, perfmon, task manager)to try and get to the root cause but there seems to be a myriad of issues.

One thing I have noticed is that MsMpEng.exe (part of defender I believe) is continually running against a whole bunch of files and getting fairly long disk response times.

Question is what is this doing running??

MsMpEng is the real time AV service, the heart of your Defender protection.

Service Name	File Location	Description
Windows Defender Service (Windefend)	C:\Program Files\Windows Defender\MsMpEng.exe	This is the main Windows Defender Antivirus service that needs to be running at all times.

https://docs.microsoft.com/en-us/win...ws-server-2016


Sometimes it can get out of hand...

https://answers.microsoft.com/en-us/...1-abbcf5dd4590

perhaps that is why I add an "exclusion" to the MsMpEng.exe file so that Windows Defender won't have to scan it's own MsMpEng.exe file. I had been doing that since W8.1 and it also works in W10

I added as an exclusion but the Real Time detector still scans things in the exclusion list. I suspect that this is only excluded during quick and Full scans which in my case are done overnight and do not affect the user.

If you disable Windows Defender Real Time protection via registry or if you have Windows 10 Pro you can disable it via the Group Policy Editor and then the MsMpEng.exe will never run in the Windows Task Manager background.

This is one of the first things I turn off when I install a fresh windows operating system. MsMpEng.exe is a memory and CPU hog and you do not need it. 4 years I used Windows 8.1 Pro without having active realtime antivirus software protection and I've never been infected with a virus.

The only time I was infected with viruses were somewhere a decade ago when I was downloading games and stuff from torrent. Since I stopped touching torrent my viruses stopped. With Steam, YouTube, Spotify, Netflix, etc I no longer need to download games, movies, music via torrents any more.

I now have a peace of mind. Viruses don't usually enter by themselves. They come usually in the form of software, programs and so called cracks that disguise themselves as something innocent.

If I ever need to scan my computer for viruses I will do so manually. But most of the times the antivirus software is such a memory hog it is like a virus in itself!

BLaZiNgSPEED said:

This is one of the first things I turn off when I install a fresh windows operating system. MsMpEng.exe is a memory and CPU hog and you do not need it. 4 years I used Windows 8.1 Pro without having active realtime antivirus software protection and I've never been infected with a virus.

That you know of. If you have no anti-virus, you can't know you have a virus unless it does something noticeable to you.

It's extremely risky to tell other people what they do or don't need, especially when you have no idea how they use their computer, or what they do with it. Just because YOU don't think you need it doesn't mean others are exactly like you.

Mystere said:

That you know of. If you have no anti-virus, you can't know you have a virus unless it does something noticeable to you.

[/COLOR]It's extremely risky to tell other people what they do or don't need, especially when you have no idea how they use their computer, or what they do with it. Just because YOU don't think you need it doesn't mean others are exactly like you.

If you have doubts about whether you have a virus you can always manually scan your computer and see for yourself. No, it is not extremely risky because if you don't download crap, you don't get crap. It is like HIV, if you don't have sex, you won't get it.

Like I said 4 years prior to using Windows 10 I had 8.1 and a virus never entered. I only play games from Steam, Origin, Uplay, GOG and official Retail DVDs. Movies from YouTube, Netflix, Music from YouTube, Spotify. Viruses will not enter from official sources.

Also it is not true that you won't know if you have a virus or not. You will notice symptoms. You can check your Task Manager and see if there is anything unusual running in the background. You can also check to see if svchost.exe or any other Windows component has been recently modified. If the modification was from the start of your Windows installation or from Windows update, you know it is not infected. You will also notice whether you have 100% CPU usage, unusually high memory and random freezes that are unassociated with a healthy computer.

BLaZiNgSPEED said:

If you have doubts about whether you have a virus you can always manually scan your computer and see for yourself. No, it is not extremely risky because if you don't download crap, you don't get crap. It is like HIV, if you don't have sex, you won't get it.

Again, you have no idea what the person you are responding to downloads. You are saying flatly that it's not needed, when that is simply your opinion regarding your own usage. To use your analogy, you're advocating nobody using any kind of protection because YOU don't have sex.

BLaZiNgSPEED said:

Also it is not true that you won't know if you have a virus or not. You will notice symptoms. You can check your Task Manager and see if there is anything unusual running in the background. You can also check to see if svchost.exe or any other Windows component has been recently modified. If the modification was from the start of your Windows installation or from Windows update, you know it is not infected. You will also notice whether you have 100% CPU usage, unusually high memory and random freezes that are unassociated with a healthy computer.

I specifically said "unless it does something noticeable by you". Many people are not as technically savvy as you believe yourself to be. Regardless, you don't know how they use their computer. don't tell them something like antivirus is unneeded.

Mystere said:

To use your analogy, you're advocating nobody using any kind of protection because YOU don't have sex.