Coleman's .Net Nuggets

I have the same problem. I have thousands of pictures on my PC, and I use the view-by-thumbnail option when retrieving picture files from my folders. MsMpENG was using SO much CPU that the thumbnails would not even render! Watching videos was a nightmare. When OneCare and MsMpENG was disabled, everything worked fine.

I am going to try and use the steps that you outlined above to help resolve this issue.

It seems very strange to me that MS would create a security application that cripples a PC…. Talk about poor design.

This does not really surprise me have spent hours on another forum reading all threads about the different variations of Updates from Microsoft and how, knowing the problem, even they can not come up with a fix. But now having at least partially solved that by using Windows update, manually updating office as needed, and never again using Microsoft update I am moving onto the next CPU usage hog MsMpEng.exe so will be trying the exclusion solution mentioned...yeh very poor design (this is in XP Home SP 2) and from what I have heard there is something known and similar in Vista.

I discovered this problem on my XP pro box when I was trying to gauge how bad a piece of resource-intensive code I wrote was. I was trying to use the Task Manager's CPU usage graph to get a feel for whether or not my code would have any noticeable effect on system performance. I was expecting my code to increase CPU usage by 1 or 2 percent so I had to get the background activity down to zero in order to notice the effects of my code running. Prior to installing Windows Defender, this was never a difficult thing to do. Until I stopped the Windows Defender service, the CPU usage was way over 50% and everything I tried to do on this machine (i.e. browse the web to find out what MsMpEng.exe was) was horribly slow (lots of disk swapping). I had noticed the poor performance and heavy disk swapping for several days and was starting to worry that I had been infected with some kind of nasty virus.

It seems kinda ironic that I installed Windows Defender to try to avoid having any malware or spyware bog my system down.

High CPU usage - Page 2 - Computer Forums

MsMpEng not so easy to kill either. Process keeps coming back to life like some zombie. After a few times, kill proc works though.

span you indian! you don't even know what you're talking about

okay lets please keep this on subject. my cpu is overtaken by this msmpeng.exe. i dont even have windows defender running? will try the given fix and will do more research and report back.

I have been discussing this with Microsoft Supprt. Problem came with the June'07 monthly update of Vista. I first found out that when Flexnet License Manager (for PhotoShop CS3) wants to access the internet, MsMpEng loses control and loops for exactly 300 seconds, before it is killed because of a timer overrun. Same happens when Adobe Update Manager or an unistaller want to do something on the web. Support says "they are working on it".
I turn off OneCare Virus and Spyware scanner before launching any of these programs and switch it back on when finished.
If it is not solved with the August update of Vista, I'm going to throw OneCare off and buy something intelligent like F-secure.

Hey guys, whats the conclusion? What does the poor old home user do? Where do we find an explanation is plain English step by step procedure to fix kill this crap utility.

just uninstall it, there are better programs out there to deal with spyware and malware

In my limited experience, Msmsgs.exe is just one of a number of MS dlls that have come to attention due to excessive disc activity. Other offenders being msmpEng.exe, wgatray.exe, wgalogon.exe, msmpCmd.exe, svchost.exe etc.
In seaching forums to deal with these annoyances,I have found that users have devised several creative strategies. Renaming, moving, deleting, disablling in the Registry, changing Startup status etc. etc.
It appears there are 2 issues here:
1. Disable and leave the file intact in case it it needed in the future.
2. Delete completely.(Which is not easy, as Access is denied in some instances)
My question is can we come up with Strategy for the home user that is simple to undo and not going to have drastic future implication and make a bad situation worse?

Yes, I am seeing same issue CPU and memory use, causing mouse to freeze it seems, I disable MsMpEng and mouse pointer is fine.

what are u talking about apached noob... msmsgs is windows messenger... (the old windows version of msn messenger)
u can kill it with msconfig.exe or delete it..) and svchost is ur internet connect

my prob now is the 2 indows defender processes that are under the 'SYSTEM' (user) in my taskmanager...(taakbeheer in dutch)
... this is my moms pc.. mine is 101% prob free cuz i know how to NOT break everything

It seems to me that if you not part of the solution your part of the problem. I'll try to follow the 1st posting ang reduce it to people speak.

I noticed that this process appeared after I installed Windows Defender (on Windows XP SP2). Once in a while, Windows Defender wants to do a "quick scan" of my computer (which takes about 10 minutes) and the computer is completely unuseable for those 10 minutes.

When I found this forum:
http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=1485433&SiteID=2
I found that my problem is that I have McAffee Antivirus + Microsoft Defender running in parallel and competing for resources.
According to that forum, if I have an antivirus program, I should not use WindowsOneCare (Windows Defender is one component that is available for Windows XP).

Average User: do you trust Microsoft One Care with the "care" of your PC?
YES) Remove your antivirus software as it is redundant
NO) Remove all traces of Microsoft One Care (in my case, only Windows Defender)

It's definitely tied to Windows Defender and it happens after you leave your system idle for a while.

The quick fix if you don't want to go through all the steps, etc. is to open Task Manager and under the processes tab select the msmpeng.exe line (If you can catch it) and End Process.

That will clear it free and another session of msmpeng.exe will start up but you will free up the processor so you don't have to restart right then.

hey guys.. im stuck... got no idea to how to make this thing stop eating my CPU!!
yes yes i may be a dumb blonde but me and computers aren't really good friends... but i do know MsMpEng.exe is killing my pc..
i end the process in the task manager.. but it keeps coming back n i want it gone for good!!

can someone explain this to me in noob terms please???

thanks :)

Was getting this problem both on my desktop and laptop (both XP SP2). Applied the following change to both and haven't had the problem since.

Run Windows Defender from the start menu. Click on Tools then Options. Scroll down to Advanced Options. Where is says "Do not scan these files or locations" click on the Add button. Browse to the folder where Windows Defender is installed (c:\program files\windows installer) and click OK. The path c:\program files\windows installer should now be shown in the field. Click on the Save button. Thats it.

Mistake in my previous post ... the path should be :

c:\program files\windows defender

phil - you're the man! This problem's been bugging me for a while. Finally took the time to investigate traced it to MsMpEng.exe, then saw your post here. First after opening Windows Defender, I found it was in the middle of a scan, so stopped the scan, then followed your directions - instant relief!

alright every one this is one big problem every one seems to have with windows live onecare... for my part i like testing out new programs... just go into your into your control panel and and remove programs and get rid of it... for one thing it never catches most of the viruses like it should... i build viruses and it never catches them ever... as for the windows defender i got that on my pc but sometimes the MsMpEng.exe keeps sometimes going up the msmpegn is a microsoft maping engin for the live one care and the defender which is a basic operation to run in ur back ground to gard u against possible attacts from viruses or any harmfull things.. it ends up going crazy cuz it has no idea what to do... i say get rid of them .. if u want a good program look for a program called trojan hunter that program is one kick ass programs and it deleted some of my virsus i made i was sad of course but glad it works... this is mentioned for newiebees and good for experiance users... now remember no antivirus is giogn to get every thing ... soo always have a back up... like a partition and for those of u that don't know wha that is its just basicaly splits ur hard drive soo virsuses wont affect ur data and u can format the part that is infected... theres no really good protection i say dont go into bad sites u know u shouldnt be giong into in the first place and get rid of that gay asss live onecare its a pice of crap... get ur self trojan hunter it gets what mechafee and norton and pc antiviurs dont get... i fix computers all the time soo i come acrrosss this all the time just saw this post this is the right way if u want ur pc to f up then its up to u to do as u wish its ur pc

and sorry for my bad grammer just noticed it. well like i said if u didnt understand me, get rid of windows live one care and windows defender, in your add and remove porgrams ... you simply go into ur control panel and well add and remove programs ..... doing this will stop that MsMpEng.exe from running your cpu soo high... Windows live one care and windows defender dont do as they supose to any ways



go with torjan hunter its the best better then any anti viruse program i tested soo far,,, avg is crap, reg mechanic is crap to go with regvac it actually does what its supose to

I came upon this little nugget via the MS knowledge base. The resource will spike during a scan, but the scan appears to go a little faster? My laptop went through a normal scan approx. five to ten minutes after booting. The scan lasted under five minutes spiking at times but never over 50% CPU.

http://support.microsoft.com/kb/892489

In recent weeks, I have been having problems with Windows Explorer suddenly freezing or crashing and with the power off options misbehaving. Also started to notice a lot of disk activity due to MsMpEng.exe, so from reading this feedback decided to remove Windows Defender completely. Lo and behold all the problems now seemed to have disappeared although it's still early days, so currently my advice to anyone having these sort of problems would be to REMOVE WINDOWS DEFENDER if in doubt. (NB I do have other protection software running)

People get a clue....UNINSTALL One Care it is defective. Bill Gates is a liar and a criminal. That process is in place to kill your PC so you have to buy a new one (with vista)....

ANY free AV is just as good at detecting malware as ANY paid for AV

I suggest you use AVG free edition

avg is crap!!!! please stay as far away from that garbage as possible!!!! it is nothing but pure crap and is the biggest scam cause it never ever works!!!1!!!!!

I installed Windows defender about 3 days ago, and told it to do a full scan........I think it scanned every pc in my town!!!......it started at 10pm.........when I got up at 6am it was still scanning !....I mean, what a joke......left it going all day, came home that evening and it had finished and found some stuff, so told it to do its thing..........and that took hours!!!.........couldn't do anything on pc meanwhile either, so, in the end shut the damn thing down.
Rebooted this eve, and MsMpEng.exe was hogging the limelight again...........so killed it.......might uninstall the damn thing altogether......

people when proses uses 50% of cpu and newer more that means you have 2+ core CPU, and that process uses 100% of 1 of the cores . witch is very bad, in single core CPU your would be dead in the water

Ive been using Windows Defender (and more recently OneCare) since it was available in Ireland and its the ONLY software of its kind that i have found in 10 years that runs quietly and DOESNT hog CPU. I have never had the problem that is listed above. I have to wonder why this seems to happen to some people and not others? I think OneCare is an excellent piece of software, as was Defender. I have tried AVG and all the other usual recommendations and found them all to be crap.

Just thought i would mention that, its always good to have both sides of the story...

RH

AM RH
You're an idiot

You're a fking idiot.


****
People get a clue....UNINSTALL One Care it is defective. Bill Gates is a liar and a criminal. That process is in place to kill your PC so you have to buy a new one (with vista)....

ANY free AV is just as good at detecting malware as ANY paid for AV

I suggest you use AVG free edition
****

Windows Live OneCare is probably great for users who browse the internet a bit and check their e-mail. However, if you do any kind of "advanced" stuff with a computer, you're pretty much screwed.

When I try to FTP with Dreamweaver, MsMpEng locks it up and the connection times out.

Visual Studio Web Developer sets up temporary web servers so that you can test your ASP.NET code on your local machine...and even though it's a Microsoft product and virus free code, MsMpEng locks it up and it takes about 3-5 minutes for a page to load if it ever does.

I was actualy browsing live.com today, which you'd think that OneCare would give it's own website some measure of trust...but no...it locked up my browser while trying to browse live.com to find a solution to this problem.

The ONLY solution that I've found is to go into Windows Live OneCare, click "Change OneCare Settings", then click on the "Viruses and Spyware" tab and turn "Virus and spyware monitoring" OFF.

If you do this, however, that means that it won't find a virus unless/until you do a virus scan of your computer, which can often be too late. So, I pretty much leave that window open and toggle it on/off as needed.

For the most part, if you're not going to untrustworthy sites or openingup e-mail attachments, then you are safe from the vast majority of viruses...but it's still not ideal to have to turn monitoring off.

Personally, Norton is the only virus software that I've never had problems with...well, I've had problems, but nothing as major as this.

How do you uninstall Defender... i see it in my add/remove programs list, but there is no remove button.

furthermore, it doesnt exist in my start menu

Use NOD32... I've tried pretty much everything on quite a few different PCs and OSes. Nothing I've found works better or more stealthily...barely know it's there. Norton is a resource hogging piece of junk. AVG is well, average (lol). McAffee is the McDonalds version of Anti-Virus... Just my opinion, but if you haven't tried NOD, your missing out... and no, it doesn't have anything to do with Command & Conquer.

I agree with ALL the negative comments about Defender! It drains and squeezes the life out of my old pc. I just bought NOD32, and can't wait to get rid of the LIFE-SUCKING NORTON VIRUS SCAM!!! Ya, I mean SCAM!!!!!
Charley-Dallas

don't know much about NOD, AVG and all the other crap you guys seem to be ranting about. I also don't know how good onecare is for catchin stuff... BUT I do know that if MsMpEng.exe is hogging CPU and you're running OneCare, its the "performance plus tune-up" running. this is the total system scan that it will try to run as often as you've set it up as per your OneCare settings... You can manually stop the "tune-up" from the main screen. ...but if you want to use the brut force and ignorance method... go ahead and uninstall. just keep in mind that all these scanners have to hog CPU at some time to actually check your system...

jjjj got a good point; one care is doing it stuffs behind the scene, but it take too much cpu out of any systems; it does it whenever it updated and then does the scan. The definition is about as useless as anything else once the system is infected by mal-wares. The best way is just format the pc and restore a copy of the os and its appz. I tried most of the anti-spam/spyware/anti-virus from most of major players in the market plus the mom and pop virus removers; all come down to backup my stuffs and format then restore a fresh image onto the HD. Well, I download a bunch of malwares into my test pc and tried all those things to see which one actually work; to name a few: SpyHunter, SpyBotSnD, AVG all packages, Norton, One Care from MS, and etc.; but non of them seem to clean up everything; there's something that those software can't clean. Bottom line; those stuffs that I did was part of my job. but good luck to everyone on finding the solution to your problems. I know for sure that there will be problems once the system got infected by malwarez.

My next computer is going to be Apple, sick to the teeth with MicroSoft. svhost and msmpeng have my machine working like an old clapped-out steam engine. Maybe it's a ploy by MS to force everyone to upgrade their Windows, talk of monopoly. I trade currencies and I need split second decisions sometimes, and just can't make them.

Patty, why don't you just download Freespire and install it. It's a easy to use version of Linux that will do anything Apple will for free??

The web page designer of this website is a M$ idiot too. Firefox is highly recommended for this affliction.

are you guys sure that it isn't just starting a scheduled full system scan? you can change it in the preferences. I just noticed the process, stopped the scan and it seems fine now.

how do you get windows defender program up from the onecare?

plus i dont want to get rid of onecare i just spent 40 pounds on it!

my solution was to run services.msc and then disable the windows defender service. No problems anymore

I have come to the conclusion that Windows Defender is crap. Back in the day, it was OK as it did find and remove some harmful stuff, now, it just sucks out loud.
I've been fighting this software for a week now and, to be honest, I'm over it. I just removed it and my PC is fine now. I'll just have to use one of the ten million other anti-malware programs available.
If you bought One Care, I would try to get your money back. Or, at the very least, get your money's worth of tech support to get the issues resolved. Keep their tech on the phone for a few hours until they get it right.

PS

For St. Elsewhere et al see for instance:
http://www.computerhaven.info/forum/printable.aspx?m=37712

which is actually helpful without posts by idiots about alleged idiots.

Moved on!

Having not reviewed this thread closely until some time off, I see it has taken a turn for the worse. Certain inappropriate comments submited by others have been removed. I did check out the link provided by "just passing by and moving on!" and it didn't seem to provide a lot of guidence. If you would like to obtain nuggets straight from the source, I suggest you check out the Windows Live OneCare Forum at: http://forums.microsoft.com/windowsonecare/default.aspx?siteid=2 for additional help. I have upgraded to version 2.0 lately and haven't run into any problems. I've used Norton and McAffee in the past with the same result. As time goes on, software upgrades continue... the hardware doesn't keep up. As you may have guessed it... this tends to drive the market!!!

This thread will continue to be open for helpful comments. As with everything, a few usually ruin it for the many.

Go to this website and click on the link that says

Click to run a free scan for msmpeng.exe related errors.

Download this program and run it to fix your registry.

Might help

If you guys install the FREE "Process lasso" you will see THE SOLUTION. Automatically lowered process priority!!

If you are having problems with Defender, it's likely that you downloaded the wrong version. From what I learned tonight in class, if you don't install the correct version, you'll run into problems with it overloading your system.

I have vista sitting here with all of the MS virus stuff installed on it. The comments here are mostly all correct. virus and spyware "monitoring" is looking at *every* packet coming into the machine thru the network connection. So this means that FTP, Sockets, etc. based applications will go Real Slow and web pages, etc. won't appear to be held up that much. So the advice to turn off virus and spyware scanning while running apps that do a lot of TCP/IP stuff and write to the disk continuously is good advice.
Virus identification is remarkably difficult to do so no wonder that we all hate Norton, McAfee, LiveOneCare, etc.
I agree that Norton is probably the least of all of the evils.

MsMpEng.exe FIXED HERE.

I recieved these instructions from One Care Live. I told them I was not renewing with them unless they had a fix. On the phone the lady told me it was NORMAL for MsMpEng.exe to use 80% CPU. She also told me any other security will not solve the proble. I am a newbee so I just told her I will take my chances with someone else. I was going to try the Trojan Hunter as advised from someone in this thread when I recieved an email from the lady on the phone with the folowing instructions

Kindly try this troubleshooting step:

1. Go to your control panel and open add/remove programs
2. On the left pane, click on add/remove windows components
3. Make sure that there's a check mark on NETWORK
4. After clicking Network click on details
5. Uncheck the box for Peer to Peer then click on next
6. If it ask you to insert the disk, disregard it and just click cancel

I now longer have any problem with MsMpeng.exe. Maybe my computer is not as secure, but at least my CPU is making me $ instead of frustrations. Please let me know if this is what youve been looking for or just the same as turning of your security.

The problem is Windows defender is doing a scan, the simple solution it to open Windows defender and click stop scan. i hope this information helps you.

I agree with VI. I installed Process Lasso and in the first instant it lowered something called MsMpEng.exe to 'below normal' priority. That is how I got here, I was trying to figure what it was and did I get a revelation. Now everything seems to run orders of magnitude faster.

i keep trying to kill off MsMPEng.exe, and of course it restarts. I've been scrolling through the comments above.

1-I've tried to kick it out of startup, but it returns each time. grr.

2-how the heck to i disable something in a "registry"?

3-i installed LiveOneCare and it removed WindowsDefender for me, so i can't even run that in the start menu.

4-the guy above who says to use the add/remove network and peer-to-peer stuff... i followed your options and i did have a check next to network, and no check next to peer, and it never gave me an option for "next". so that fix doesnt work for me.

5-I keep getting this expired anti-virus warning box in red popping up in the right corner. it freezes my programs and when this happens, and i thought i deleted the program running it, but i guess not. i can't find it in add/remove.


Any more suggestions?!
--allen

Hi there!... this problem is ocurring in Xp Home Edition Sp2... but I did experienced when I have instaled microsoft LiveCare.. and not with windows defender!!! because windows defender was deleted by me ante instal LIVE CARE. And they wanth a reasonable price/year to have this in you're computer... a thing that is not working . You can download an trojan an instalit to youre computer and you don't experience suck of problem.... like with this MSMpEng.exe from LiveCare!. I believe that I will unninstal this and reinstal my old antivirus and spyware and internet cleaner and hijack! 3 programs but for me work.. and with windows defender!

This is what worked for me. My problem was high cpu usage (about an average of 60%) after updating to Live Onecare 2.0
After reading a few recommendation on Web forums this is what worked for me even after a reboot.
I have windows XP. Go to:
Control Panel/administrative tools/services
Right click on "peer networking identity manager" ... Then
(select to "stop" the service & take the "disable" options and the select apply and OK).

after a few seconds you will see cpu usage going back to normal.

I found that if I uncheck the; allow third party extensions in the advance tab in the Internet options. It is located in browsing, cure the MsMpEng.exe. Reduced it to 0%.

I am VERY thankful for the comments. I'd been trying to resolve this for a full week, because I was trying to install ACDSee 10, which just WOULDN'T. I thought my hard drive was going bad, so I tried EVERYTHING (even the almost useless System Restore, backups, playing with the Profiles). A full week wasted! My computer expert made his typical comment: reinstall windows. NAH! After seeing your comments identifying MsMpEng.exe, I left Defender installed, went into its settings and turned them all OFF. Not only do I have ACDSee installed, but my computer is running nice & smooth! Thanks!

Thanks for the help. I have been bugged by system stalls for 6 months. Found msmpeng.exe in task manager and figured it may be the problem. Google sent me here. I uninstalled Windows Defender and everything looks good.

I didn't even know it was still running. I had installed it a while ago, tried it, wasn't impressed and took it out of my startup. Evidently it uses register settings to start running every time you reboot.

I really hate software that does that, it is even worse than software like RealPlayer, Quicktime and Adobe Reader that drop in a startup on reboot command whenever you run them.

I think this program, "MsMpEng.exe," is actually downloading information from "my" computer and I've disabled it. We've entered a technological POLICE STATE. Where is Osama Bin Landen??? We're losing our liberties, people are getting tasered, new gadgets are already developed that are much worse than the taser and WHY SHOULD ANYBODY THINK THAT THE PROGRAMS THEY DOWNLOAD FROM SO-CALLED RELIABLE TRUSTABLE SOURCES ARE REALLY ALL OUR GOOD HELPING FRIENDS?!!!!

hey i just had this problem, i just used 'uniblue speed up my pc' software, fixit instantly. u get a free copy from www.torrentz.com

Odds are that when MsMpEng is taking up your CPU, that Windows Defender is running a system scan. When your CPU is being hogged by it, open up Windows Defender (Try Start-Programs and look for Windows Defender). When you open it, it will tell you if it is currently doing a scan. Defender runs scans on a schedule--see Tools->Options, and maybe change it to scan at a time when you're not using the PC, and perhaps reduce the frequency of the scans. (Note: the Tools->Options are not available while a scan is being run--you'd have to stop the scan first.) Of course, the less frequently you run the scan, the less protected you are from the malicious software that Defender is designed to protect you from.

I just accomplished the steps explained by phil who posted above on 9/5/2007. It was simple and more importantly, it got my defender's scan down to 4 minutes without every going above 30 percent CPU usage. Thanks phil!!

Clocked over 10 hours of phone support from MS! Yup...Defender is the hog. Thanks guys. What is the best antivirus system out there for XP serv pk 2? (Currently I have One Care)

I just went into windows defender and excluded all my drives from being scanned and set the scan time to 0300. probably redundant but seems to have worked.

i couldnt find any traces of windows defender on my comp for some reason. but i solved it another way
steps:
alt+cntrl+delete opens task manger
click processes tab
find msmpeng.exe
right click and click end
onecare icon will turn red
then click on it
click change settings on the left side
click viruses and spyware tab
click exclusions
add this folder: c:/program files/microsoft windows onecare live
done!

I went to Window Defender on my desktop list of programs, clicked on it, clicked on options and unchecked everything.
I then got a message that Windows Defender is turned off and I should be careful - hah!
I just did this so am not sure it won't come back after a restart but, if it does, I will remove it altogether per some of the suggestions above. If it doesn't come back, this solution would seem to be the simplest and the program is still there if I ever want to use it again.

I went to Window Defender on my desktop list of programs, clicked on it, clicked on options and unchecked everything.
I then got a message that Windows Defender is turned off and I should be careful - hah!
I just did this so am not sure it won't come back after a restart but, if it does, I will remove it altogether per some of the suggestions above. If it doesnt come back, this solution would seem to be the simplest and the program is still there if I ever want to use it again.

I went to Window Defender on my desktop list of programs, clicked on it, clicked on options and unchecked everything.
I then got a message that Windows Defender is turned off and I should be careful - hah!
I just did this so am not sure it won't come back after a restart but, if it does, I will remove it altogether per some of the suggestions above. If it doesnt come back, this solution would seem to be the simplest and the program is still there if I ever want to use it again.
I use Kaspersky suite which does a good job and does not hog the CPU like McAfee and Norton.

I went to Window Defender on my desktop list of programs, clicked on it, clicked on options and unchecked everything.
I then got a message that Windows Defender is turned off and I should be careful. I dont think so.
I just did this so am not sure it won't come back after a restart but, if it does, I will remove it altogether per some of the suggestions above. If it doesnt come back, this solution would seem to be the simplest and the program is still there if I ever want to use it again.
I use Kaspersky suite which does a good job and does not hog the CPU like McAfee and Norton.

I just got slowed down by msmpeng.exp. It just showed up when I got an adobe upgrade notice, just like Marco memtioned inhis 7/12/2007 12:28 AM post. I dumped the request and it let go of my CPU.

I always check Task Manager when CPU runs hard, and found same problem today: with MsMpEng.exe. Came back later and now running fine, so it could have just been scanning. I also had just installed OneCare a week ago, and uninstalled my McAfee (which also was a CPU hog). So after reading all of these posts, I have followed Phil's from 9/5&6/07, and similar to "S" 3/4/08. I have figured out that since I have One Care, I do NOT have Windows Defender... same MsMpEng.exe file, just different named folder, so follow whichever one you have. For current version of OnceCare, open it, under Quick Links, click on Change Settings, Click on Viruses and Spyware, click Exclusions button, click Add Folder, and navigate to C:\Program Files\MicrosoftWindows OneCare Live\Antivirus and click OK. But I think I will also try Process Lasso just for grins as this type of CPU problem drives me nuts!

phil, thanks for your lifesaving instructions! Ah, the silence now that my hd isn't running constantly.

everytime I hear it running it rarely shows in the system tray but find it is defender running a normal system scan. just go to controle pannel click on software explorers and if it is running you will see it and just stop the scan. change your settings as to when and how often you want it to run

Great...Great..Phil.
You are really The Saver!
Your suggestion was brilliant.

Good Luck Everybody.

inf my experience i had a problem with spoolsv.exe eating 99% CPU , every time i killed the process MsMpEng.exe started to suck up 95% of my CPU. i found the root of my spoolsv.exe problem and so far MsMpEng.exe hasnt botherd me yet :D

I deleted Windows Defender....issue resolved....

I have SolidWorks 2008, and msmpeng.exe starts up Solidworks every time it scans it for some reason.

I have defender running on 3 old P3 computers with as little as 256Mb of Ram and the systems work great... I have been using Windows defender since it was first released in Beta form and never had an issue.

I run it on both my P4 computers and no Problems!

I think the issue here is Windows One Care and not the Standalone Product Windows Defender...

Let the flaming begin... :)

4hams, you are just wrong. I have only installed Windows Defender and I suffer from this issue, so it is not Windows One Care. It's Windows Defender.

Yes, it is Windows Defender. It uses about 30 MB of memory -- one of the top Windows memory hogs. You have two options:
1. Set Windows Defender service to start 'manually' instead of 'automatically', using Windows Administrative Services tool. Then start it (with the same Services tool) whenever you want to run it, and stop it when you're through with it (using either the Services tool or the CtlAltDel Task Manager to end the MsMpEng.exe process).
2. Uninstall it and don't use it! Use AdAware and or Spybot.

This is typical of Microsoft -- users have to resort to third-party web sites, blogs, and technical articles for solutions that Microsoft ignores.

Everyone in this forum knows that there is a serious problem with MsMpEng.exe, however no one can offer a solution that works. If you are reading the entries in this forum, you are wasting your time. The entire forum should be deleted and replaced with a link to an article that offers a true solution.

MsMpEng.exe is the background scanning option for LiveOne Care. By ending the process you are cancelling the background virus scan. Simply change your scan settings or manually run the scan prior to shutting down the machine. It will only run when scheduled OR after the first boot/wake after a missed scan.
This one is very simple guys!

It's not that simple as far as I can tell. There is no way to prevent the scheduling of the background virus scan which eats up the CPU. When you say "simply change your scan settings" I think you mean to change the settings so that you reduce the scan frequency to once/week (which is an improvement, I admit). There is no option in OneCare to turn it off altogether, unless I'm missing something.

Actually MsMpEng.exe will not be deleted/stopped by uninstalling 1 Live Care, of Windows Defender. It is a system service (not that it is doing any service for my computer) that scans your entire computer if you haven't done so recently (or it hasn't done a scheduled check in a long time), whether you have WD, 1LC. Also it will still do this even if you have scanned it with something else that is not exclusively Microsoft.

these steps kind of worked.

MsMpEng didn't stop running, but the CPU usage did drop down to 0%.

i have a decent dual-core (AMD athlon X2 3800+ 3 yrs old) with 2 GB ram, so the CPU usage didn't bug me much, it was the disk use. like i said, my pc is 3 years old, so i don't like it when my hard drive is running at full speed cuz 1c is running stuff in the background making my HD click a bunch of times.

i'll be back later to let ya know if it's still a good fix =)


***i couldnt find any traces of windows defender on my comp for some reason. but i solved it another way
steps:
alt+cntrl+delete opens task manger
click processes tab
find msmpeng.exe
right click and click end
onecare icon will turn red
then click on it
click change settings on the left side
click viruses and spyware tab
click exclusions
add this folder: c:/program files/microsoft windows onecare live
done! ***