How to Fix an Antimalware Service Executable Error in Windows

Stop Windows Defender from hogging system resources

The Antimalware Service Executable, also known as MsMpEng.exe, is a core component of Windows Defender, the default security software built into Windows 10. If your computer runs slow, it could be because MsMpEng.exe is hogging CPU resources. Problems with the Antimalware Service Executable can prevent Windows Update from working properly.

Instructions in this article apply to Windows 10.

Windows 10 Task Scheduler

What Causes Antimalware Service Executable High Resource Usage?

MsMpEng.exe can make a hard drive or SSD work particularly hard when it conducts a system scan. Like other antivirus software, Windows Defender periodically performs scans to make sure nothing is running on a PC that shouldn't be, in addition to real-time monitoring. That shouldn't be a problem on higher-end laptops and desktop PCs. Still, the Antimalware Service Executable has been know to use a disproportionate amount of system resources in budget laptops.

You can see how much of the CPU each active file and process uses in the Windows Task Manager.

How to Fix Antimalware Service Executable High CPU Usage

If MsMpEng.exe is hogging system resources, wait a few minutes. It's possible that the system is undergoing a full scan, and that once it's finished, the resources used by that process will go back to normal.

If you want to make sure that a scan like that doesn't happen in the future, you can also take some steps to have more control over what the Antimalware Service Executable does and when.

  1. Change the Windows Defender schedule. Changing when Windows Defender runs its scans can give you a better grasp of the system's resource usage. This change allows you to control exactly when scans take place and how much system power it draws.

  2. Add MsMpEng.exe to the Windows Defender exclusion list. A bug can cause the Antimalware Service Executable to scan itself, using a ton of system resources in the process. To prevent this from happening, set Windows Defender to exclude MsMpEng.exe.

  3. Scan for viruses and malware. It's possible that malware caused problems with Windows Defender and made it use up too much of the CPU. Run a scan with a third-party antivirus tool to make sure that's not the case.

  4. Disable Windows Defender. Windows Defender is a great security tool, but if you exhausted everything else, the nuclear option is to disable Windows Defender entirely.

Turning on Windows Defender can leave a PC vulnerable to security threats. If this fix made it possible to update Windows successfully, reactivate Windows Defender when you're done, and make sure only the Real-time protection option is enabled.