Windows Defender (msmpeng.exe) huge memory usage + commit size making PC unsuable until restart

My issue ended up resolving after:

1.  Installing some other antivirus program (and disabling Windows Defender)

2.  Uninstalling that antivirus program a few days later (and reenabling Windows Defender)

Maybe a long shot, but could work

Hi,

Not sure if I'm seeing the same problem, though if my PC is left idle for a while, Windows Defender will utilize all available memory and seemingly load one of my CPU cores at 100%. It doesn't relinquish this memory or CPU time when I am using the PC and the only way to resolve the problem is a reboot.

I'm considering a reinstall of Windows as a potential solution, though I'd prefer not to have to waste my time like that obviously if there is a simpler solution.

Hi,

I cannot think of any changes I have made recently that would trigger the issue.

I'm not using any third-party antivirus. The real-time protection for Windows Defender is disabled (I disabled it a long time ago). It only runs scheduled or on demand.

The error messages I receive vary between applications. Chrome and Opera give  "Out of Memory" errors when loading pages or new tabs.  Some applications start crashing without detailed error messages.  I they are all symptoms of the system running out of memory.

It was refreshing to read this, basically confirming what I've suspected to be true for some time now.  It's nice to hear it from someone with experience as a developer.  I too am a power user, just not so much in programming.

My issue looks to be the same as everyone else here.  Basically, fresh install (this week), all updates complete, done everything microsoft's way with all the defaults and changed nothing.  I've only installed Davinci Resolve, Office 2013, Spotify, and an old game.  My computer at IDLE, should not be using 10+ GB of Memory!  My linux systems run on less than 1/2 GB, and NEVER have problems like this!  Also, to further insult our intelligence, they don't show enough details in the task manager to determine which process is the problem.  It shows "10 GB In Use", but the total of all the processes running is less than 1 GB (and yes, I'm showing all users).  Even looking at the resource monitor, the largest process (MsMpEng.exe) is only 126 MB commit.  I figured it must be a memory dump problem using up all that memory.

Too bad I can't kill the process "access denied" even though I'm admin.  Also, turning realtime protection off didn't work for me.

Sometimes I wonder why I even bother searching for an answer from Microsoft.  What I would give for full control over my computer again.  It's too bad I can't get an Enterprise copy of Win10 as a consumer, which lets you control a lot more than Pro.

Especially with all the telemetry going on on Win10, you'd think they'd catch these problems quick and fix them immediately, right?  It's clear we're no longer the customers, we're the product.

I'm not Michael, but as I said above I'm having the same problem.

I don't have ANY other security software installed - corporate environment with SCCM Deployment.

In our case, installing OTHER software as a temporary measure fixed the problem, but that's not a good solution going forward, we need Defender to be stable.

Is there an internal bug tracking system you can raise this on? Is there already a case for it? If not, can you raise one? I am absolutelyhappy to be a source for it and provide any and all materials/logs/troubleshooting - this is driving our users (and us) nuts.

Believe me when I say that NOTHING has changed except for Windows updates going out as per usual, and the usual Microsoft answer of disabling Defender or running SFC or checking to make sure I don't have other security software installed will not suffice.