MsMpEng.exe high CPU usage on PC: How to fix it

Madalina Dinita
by Madalina Dinita
Former Managing Editor
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MsMpEng.exe high CPU usage fix
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MsMpEng.exe may sometimes cause high CPU usage on Windows computers.

In this guide, we’re going to tell you everything you need to know about this process and how to fix some of the most common issues it triggers.

Is MsMpEng exe a virus? MsMpEng.exe is a core process of Windows Defender. It’s not a virus.

Its role is to scan downloaded files for spyware, and quarantine or remove them if they are suspicious. It also scans your system for known worms, harmful software, viruses, and other such programs.

Can I stop MsMpEng.exe? Many Windows users, irrespective of the Windows version they use, have reported that sometimes MsMpEng.exe causes high CPU usage, reaching even more than 80%.

To fix this problem, you can stop MsMpEng.exe from the Task Manager.

MsMpEng.exe triggered issues

There are many problems that can occur with MsMpEng.exe, and users reported the following issues:

  • Msmpeng.exe end process Access Denied – According to users, sometimes they might get Access Denied error message while trying to end this process. To fix this problem be sure to try some of our solutions.
  • Msmpeng.exe eating memory, CPU – Sometimes this process can cause both high CPU and memory usage. This can drastically impact your performance, so it’s important to fix this problem as soon as you can.
  • Msmpeng.exe excessive disk usage – In addition to high CPU usage, disk usage problems can also appear. Many users reported that this process is responsible for high disk usage on their PC.
  • Msmpeng.exe encountered a problem – Sometimes this process can randomly crash on your PC. You can easily recognize this problem by Encountered a problem error message.
  • Msmpeng.exe running constantly – Many users reported that Msmpeng.exe is running constantly in the background. According to them, this is causing high CPU usage on their PC.
  • Msmpeng.exe slow boot – This process can also affect your boot time. Many users reported that their PC boots slowly due to this problem.
  • Msmpeng.exe keeps running – Several users reported that this problem keeps running in the background. Due to high resource usage this process can drastically reduce your performance.
  • Msmpeng.exe memory leak – Another common problem with this process are memory leaks. If this problem occurs on your PC, be sure to try some of our solutions.

Why is MsMpEng.exe using so much CPU?

There are multiple causes for this msmpeng.exe unusual behavior such as:

  • The tool is scanning its own directory
  • Low hardware resources
  • Old antivirus registry files
  • Malware installed on your computer.

There are lots of free and paid antivirus programs available, and you can choose at any moment to remove Windows Defender, and replace it with a different antivirus.

However, before taking such a decision fueled, perhaps by msmpeng.exe’s high CPU usage, you should try out the following workarounds to fix this issue.

Steps to fix MsMpEng.exe high CPU usage

  1. Prevent Windows Defender from scanning its directory
  2. Limit CPU Usage
  3. Start your computer in Safe Mode
  4. Remove Adware
  5. Reschedule Windows Defender
  6. Disable Windows Defender
  7. Disable Sample Submission

1. Prevent Windows Defender from scanning its directory

For Windows 7:

  1. Go to Windows Defender > Tools > Advanced options.
  2. Open Excluded files and locations.
  3. Copy and paste the following path -> c:\program files\windows defender.

For Windows 10:

  1. Type Windows Defender in the search bar > double-click Windows Defender.
  2. Go to Settings > select Add an exclusion (the option is located at the bottom of the page).
    Msmpeng.exe end process Access Denied windows defender
  3. Select Exclude a file and paste the following path -> C:\program files\windows defender.
    Msmpeng.exe eating memory add an exclusion
  4. Validate by clicking on Exclude this folder.

2. Limit CPU Usage

For Windows 7:

  1. Go to Task Manager.
  2. Right-click the msmpeng.exe process in the Task manager list.
  3. In the context menu, select Set affinity.
  4. Choose the cores which you allow the particular process to use.

For Windows 10:

  1. Go to Task Manager > More details > click on the Details tab.
  2. Right-click msmpeng.exe > select Set affinity > select the CPU limit threshold.

set affinity task manager Msmpeng.exe excessive disk usage

3. Start your computer in Safe Mode

For Windows 7:

  1. Reboot your computer.
  2. Press F8 as your computer is restarting, before the Windows logo appears.
  3. When the Windows Advanced Options Menu appears on the screen, select “Safe Mode with Networking” and press Enter.

For Windows 10:

  1. Go to Settings.
  2. Select Update & Security > Recovery.
  3. Under Advanced startup, select Restart now.recovery settings app Msmpeng.exe encountered a problem
  4. When your PC restarts to the Choose an option screen, select Troubleshoot > Advanced options > Startup Settings > Restart.
  5. You’ll then see a list of options > press F4 to start your PC in Safe Mode.

Find out more about fixing high CPU usage in Safe Mode with our complete guide!

4. Remove Adware

You can use specialized software to remove adware. Two of the most popular such software programs are:

  • AdwCleaner – it has more than 125 million downloads. This free software is compatible with Windows XP, Vista, 7, 8, 8.1, and Windows 10.
  • Malwarebytes – detects and removes malware, spyware, adware, and anti-rootkit tech. You can try it for free for 14 days or buy a one-year subscription for $25.95 or a two-year subscription for $41.95.

5. Reschedule Windows Defender

Windows Defender can sometimes cause problems with MsMpEng.exe and high CPU usage.

To fix this problem, you need to reschedule Windows Defender by following these steps:

  1. Press Windows Key + S and enter task scheduler. Select Task Scheduler from the list of results.
    task scheduler search results Msmpeng.exe running constantly
  2. When Task Scheduler opens, in the left pane navigate to Task Scheduler Library/Microsoft/Windows/Windows Defender. In the right pane, double click on Windows Defender Scheduled Scan.
    windows defender scheduled scan Msmpeng.exe slow boot
  3. When Properties window opens, go to Conditions tab. Make sure that Start the task only if the computer is idle, Start the task only if the computer is on AC power and Start only if the following network connection is available options are disabled. Click OK to save changes.
    conditions tab task scheduler Msmpeng.exe keeps running
  4. Open the Properties window again and go to Triggers tab. Click on New.
    new trigger task scheduler Msmpeng.exe memory leak
  5. Choose Weekly or Monthly and select the desired properties. Once you’re done, click the OK button to save changes.
    trigger properties task scheduler Msmpeng.exe end process Access Denied
  6. Now go back to Task Scheduler and make the same changes for all Windows Defender tasks. You should have these tasks remaining: Windows Defender Cache Maintenance, Windows Defender Cleanup and Windows Defender Verification.
    windows defender cache maintenence Msmpeng.exe eating CPU

This is a bit advanced workaround, but you should be able to complete it by following our steps closely. Keep in mind that high CPU usage will reoccur when Windows Defender starts scanning.

However, you can schedule the scan to take place once a month in order to avoid this problem.

Schedule your programs like an expert with the best Windows task scheduler software!

6. Disable Windows Defender

If you’re still having problems with MsMpEng.exe and high CPU usage, you might be able to fix the issue simply by disabling Windows Defender.

Before you disable Windows Defender, be sure to install a third-party antivirus software in order to protect your PC. To disable Windows Defender, you need to do the following:

  1. Press Windows Key + R and enter gpedit.msc. Press Enter or click OK.
    gpedit.msc run window Msmpeng.exe excessive disk usage
  2. Group Policy Editor will now start. Keep in mind that this feature is available only on Pro and Enterprise versions of Windows. However, you can also install Group Policy Editor on Home versions of Windows.
  3. In the left pane, navigate to Computer Configuration > Administrative Templates > Windows Components > Windows Defender Antivirus. In right pane, double click on Turn off Windows Defender Antivirus.
    turn off windows defender antivirus Msmpeng.exe encountered a problem
  4. When Properties window opens, select Enabled and click on Apply and OK to save changes.
    enable policy Msmpeng.exe running constantly

If you can’t run Group Policy Editor on your PC, you can also fix this problem by modifying your registry. To do that, follow these steps:

  1. Press Windows Key + R and enter regedit. Press Enter or click OK.
    regedit run window Msmpeng.exe slow boot
  2. When Registry Editor opens, in the left pane navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender.
    registry editor windows defender key Msmpeng.exe keeps running
  3. In the right pane, look for DisableAntiSpyware DWORD. If this DWORD isn’t available, right click the empty space and choose New > DWORD (32-bit) Value from the menu. Now enter DisableAntiSpyware as the name of the new DWORD and double click it.
    new dword registry editor Msmpeng.exe memory leak
  4. Set the Value data to 1 and click on OK to save changes.
    disableantispyware dword Msmpeng.exe end process Access Denied

After making the changes, Windows Defender will be disabled and the problem should be resolved.

7. Disable Sample Submission

According to users, problems with high CPU usage and MsMpEng.exe can appear due to Sample Submission feature. This feature sends problematic files to Microsoft for analysis.

Although this is a useful feature, it can cause problems to appear. To fix this issue, we need to disable this feature by doing the following:

  1. Open the Settings app and navigate to Update & security section.
    update & security settings app Msmpeng.exe eating memory
  2. Navigate to Windows Defender on the menu on the left and click on Open Windows Defender Security Center.
    open windows defender security center Msmpeng.exe excessive disk usage
  3. In the left pane, click on Virus & threat protection. Now click on Virus & threat protection settings.
    virus and threat protection settings Msmpeng.exe encountered a problem
  4. Locate Automatic sample submission and turn it off.
    disable automatic sample submission Msmpeng.exe running constantly

After doing that, check if the issue is resolved.

If you are not satisfied with result of the solutions suggested above, check out this article which will help you to choose another antivirus program.

Step-up your game by choosing the best software to fix high CPU usage!

Editor’s Note: This post was originally published in July 2016 and has been since completely revamped and updated for freshness, accuracy, and comprehensiveness.

Editor's Note: This article was originally published in October 2017 and was revamped and updated in February 2020 for freshness, accuracy, and comprehensiveness.
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