When the Antimalware Service Executable (MsMpEng.exe) is showing high CPU usage within the task manager, follow these steps to repair the issue.

MsMpEng.exe, referred to as Antimalware Service Executable is a Windows Defender processes. To become more specific, the MsMpEng.exe process accounts for real-time protection. As such, the procedure always runs without anyone's knowledge to supply real-time protection from viruses or malware threats.

Under certain situations, the antimalware service executable may cause high CPU usage in Windows 10. A few of the reasons for MsMpEng.exe's high CPU usage include although not restricted to virus infections, over scanning, etc.

Fix Antimalware Service Executable High CPU Usage

When the Antimalware Service Executable's CPU usage is elevated, stick to the steps below to fix the problem.

1. Check for Any Infection in your System

The foremost and foremost thing you should do is find out if the body is have contracted any virus, malware, or adware. Whenever a product is infected, Windows Defender is actively attempting to take away the infection from the system. This leads to high CPU usage.

These are the steps to scan Windows 10 with Windows Defender.

Open the beginning menu.
Look for "Windows Security" and open it.
Select "Virus and threat protection".
Click the "Scan options" link around the right page.
Choose the "Full scan" radio option.
Click on the "Scan now" button.

As soon as you click the Scan Now button, Windows Defender starts the scanning process. Depending on the body, the entire scan may take a substantial amount of time to complete. So, sit back and wait until the scan finishes.

If Windows Defender found any threats, it will remove them automatically.

After removing any malware or confirming that the system is not infected, proceed to the below solutions when the problem still exists.

2. Exclude Windows Defender Folder

Under certain situations, the real-time malware protection engine tries to scan itself for unusual behavior and results in Antimalware Service Executable to utilize a large amount of system resources.

To stop Windows Defender from scanning itself again and again, you are able to exclude Windows Defender from the usual scan. Personally, this is actually the method that helped me. There is a good chance it'll work for you too.

Press "Windows Key" to open the beginning menu.
Search for "Windows Security" and open it.
On the right page, click "Virus & threat protection".
Click on the "Manage Settings" link under the "Virus & threat protection settings" section.
Scroll and then click the "Add or remove exclusions" link.
Click on the "Add an exclusion" button.
Select the "Folder" option.
Go to "C:\ProgramData\Microsoft\" folder.
Choose the "Windows Defender" folder and click on the "Select Folder" button.

As soon as you click the Open button, the Windows Defender folder is going to be added to the exclusion list.

Once added Windows Defender will not scan itself constantly. This will reduce the overall high CPU usage by MsMpEng.exe process or Antimalware Service Executable.

3. Turn Off Real-Time Protection

If the above method did not work then as a last-ditch effort try disabling the Windows Defender's real-time protection. Because the Antimalware Service Executable's high CPU usage is caused by real-time protection, disabling it will instantly solve the issue.

Note: I do not recommend disabling real-time protection completely. Treat this process only as a temporary fix.

Open the Start menu.
Search for "Windows Security" and then click the end result to spread out it.
Select "Virus & threat protection".
Click "Manage settings" under "Virus & threat protection settings" on the right page.
Switch "Off" the option under "Real-time protection".
Click "Yes" within the UAC prompt.

As soon as you do this, the real-time protection will be disabled. Since Windows no more scans your system continues in the background, the Antimalware Service Executable CPU usage will disappear.

Again, case a temporary fix. DO NOT disable real-time protection for longer periods of time.

4. Use Third-Party Antivirus Solution

When the above methods didn't work for you and the Windows Defender's CPU usage is so high that you cannot make use of your system, ditch Windows Defender for third-party antivirus applications like Avast or AVG and Malwarebytes Anti-malware.

Just upload Avast or AVG and Windows Defender will disable itself. Since Windows Defender is not the active antivirus solution, the MsMpEng.exe high CPU usage won't be an issue. Moreover, additionally, you will obtain a little more security compared to Windows Defender.

Along with regular antivirus software, I additionally recommend you install Malwarebytes for better protection from malware.

I hope the above methods help fix Antimalware Service Executable high CPU usage in Windows 10.