How to Fix an Antimalware Service Executable Error in Windows

The Antimalware Service Executable is a process that you're unlikely to come across unless there's a problem. Unfortunately, those do crop up from time to time and can lead to your system slowing to a crawl as it sucks up your CPU and disk cycles, forcing you to take the time to fix it. Fortunately, Antimalware Service Executable high CPU errors aren't too complex to fix.

What is Antivirus Service Executable?

The Antivirus Service Executable, also known as MsMpEng.exe, is a core component of Windows Defender—a default antimalware, anti-exploit, and anti-ransomware piece of software which runs in Windows 10 by default. It's a great companion for an effective piece of antivirus software and should be kept running at all times if you can do so.

But like many other facets of Windows, it can run into problems from time to time and that's where you'll find Antivirus Service Executable errors, and process resource hogging.

What Causes Antivirus Service Executable High Resource Usage?

The most common reason that MsMpEng.exe is using heaps of your CPU's power, or making your hard drive or SSD work particularly hard, is because it's conducting a system scan. Like antivirus software, Windows Defender, and by extension, its process, MsMpEng.exe, periodically runs scans to make sure there's nothing running on your PC that shouldn't.

That takes system resources. As does the real-time monitoring of Windows Defender. That shouldn't be a problem on higher-end desktops and laptops, but those with entry-level hardware may find that Antivirus Service Executable uses up a disproportionate amount of system resources.

How to Fix Antivirus Service Executable High CPU Usage

The first way to fix the problems caused by MsMpEng.exe's high system resource usage would be to wait it out. It's possible that your system is undergoing a full scan and that once it's finished, the resources used by that process will go back down to normal.

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

Change Windows Defender's schedule. Changing when Windows Defender runs its scans can give you a much better grasp on your system's resource usage, as you can control exactly when scans take place and how much of your system's power it draws.
Add Antimalware Service Executable to Windows Defender's exclusion list. One of the weird bugs that sometimes causes the Antimalware Service Executable to use a tonne of system resources, is when it scans itself. To avoid that happening, you can add the Windows Defender process to the Windows Defender Exclusion list.

The exclusion you want to add is called MsMpEng.exe.
Scan for viruses and malware. It's possible that an odd bit of malware is causing problems with Windows Defender and making it use up far too much of your CPU or disk time and energy. Running an antivirus scan is a good way to make sure that's not the case. How to so very much depends on what antivirus you're running, but our guide on how to properly scan your system will give you some helpful tips.
Disable Windows Defender. Windows Defender is a great security tool, but if you've exhausted everything else, the nuclear option is to disable Windows Defender entirely. This step is only recommended if and when you've completed the previous suggestion to scan for malware.

If this works for getting Windows updated, we'd suggest re-enabling Windows Defender by retracing your steps, but toggle Real-time protection on instead. If this causes problems for future Windows updates, consider leaving Windows Defender off, but know this weakens your overall system security. Make sure you have a robust antimalware solution in place.