How to Fix High CPU Usage by Antimalware Service Executable (MsMpEng)

MsMpEng.exe is a process that’s known as Antimalware Service Executable. It’s used by Windows Defender and it’s also known as Windows Defender Service. If you are using Windows Defender, it continuously scans files, connections, and programs. So, you see a high CPU usage error.

The error again appears if you use the “Full Scan” service to scan all files, folders, and apps. It may appear when you wake up the computer from sleep or when you connect it with a network. When it starts scheduled scanning, you again face this error. It may cause lagging, hanging or delayed response of the system. The reason is that your system is completely hijacked by Windows Defender. Nothing is wrong with the app or with your system. Let it continue scanning and wait for a few minutes until it completes the scan. If you have huge data, it may take more time. You should have some patience and wait until the scheduled scan is over.

So, if you experience the error during a scheduled, custom or full scan, let it continue the job. If you experience it when the computer wakes up from sleep, or when you connect it with a network, follow the solutions here.

Method #1: Repair the Corrupt Windows Defender

It may be due to the corrupt or damaged files of Windows Defender. Check Windows Defender and repair the files by using the Reimage Plus tool. Click Here to download Reimage Plus and run it once it’s downloaded. It will repair the corrupt or damaged files of Windows Defender. Reboot system once the repairing process is over.

Method # 2: Reschedule Windows Defender

You can reschedule Windows Defender to fix this error.

  • Go to the Search and type “Administrative Tools” to launch the program.
  • Scroll down the page and click “Task Scheduler” in the list.

Task scheduler in Administrative Tools

  • Select “Library from the left pane of Task Scheduler and click “Microsoft.”
  • Now click “Windows” from here.
  • Select “Windows Defender.”

Windows Defender in left pane

  • Now, in the right pane, select “Windows Defender Scheduled Scan.”
  • Right-click on it and select “Properties” from here.
  • Select the “Conditions” tab and uncheck the options “Idle”, “Power”, and “Network.”
  • Click “OK” to apply the changes.
  • Now, go to the “Properties” again and select the “Triggers” tab.
  • Here, you will see different options like weekly and monthly, etc. Click one option according to your convenience.
  • If you want Windows Defender to scan your system on a weekly basis, select weekly and click on a particular day and time.
  • Select “OK” to apply the changes and that’s it.

Method # 3: Disable Windows Defender

If the problem persists, you can disable Windows Defender to fix it. Go to the Windows Defender.

Follow the steps here to do this.

  • Launch Windows Defender
  • Select “Properties” as shown in the image below.

Properties window

  • In the Properties window, you will see the Firewall status that is usually “On.”
  • Turn it off and select “OK” to apply the changes.
  • Reboot the system and see if it makes a difference in performance.
  • Add Antimalware Service Executable to Windows Defender Exclusion List
  • If you add Antimalware Service Executable to Windows Defender Exclusion list, it will reduce the CPU usage. Follow the steps below to add this service to the Windows Defender Exclusion list.
  • Right-click to the “Start” button and select the “Windows Task Manager” from here.

Task Manager

  • In Task Manager, check the “Antimalware Service Executable” process.

Task Manager

  • Right-click on it and select “Open File Location.”
  • Here, you will see the MsMpEng file. Click the address bar and copy the path of the file’s location.
  • Press “Windows key + I” and select “Update and Security.”
  • Here, select “Windows Defender” that appears in the left pane. Scroll down the list and select the “Add an exclusion” option from here. Now, exclude a “.com, .exe or .scr” process from here and paste the path of MsMpEng.exe here.

Method # 4: Scan for Malware

Another way to fix high CPU usage is to scan for malware. Might be a malware has infected the Antimalware Service Executable. So, use good anti-malware software and scan your system to detect and fix it. You can use Malwarebytes in this context. Click Here to download it.

Method # 5: Remove Bad Updates

Sometimes, you encounter this error when you have recently installed updates. If it’s true, you may be facing this error due to that update. So, it’s important to remove that update. Follow these instructions in this context.

  • Press “Windows + R” key to open “Run” dialog box.
  • Type “cmd” for Command Prompt and press “Shift + Ctrl + Enter” to open Command Prompt Admin.

command prompt

  • Type here the following command

“%PROGRAMFILES%\Windows Defender\MPCMDRUN.exe” -RemoveDefinitions –All

  • Press Enter and type another command

“%PROGRAMFILES%\Windows Defender\MPCMDRUN.exe” -SignatureUpdate

  • Press Enter again.
  • Exit the command prompt admin and reboot your system.

It will fix the High CPU Usage error by Antimalware Service Executable. Enjoy an error-free system.

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