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Antimalware Service Executable is a core process of Windows Defender that helps protect your computer from malware and threats. Sometimes, you might notice it using a lot of CPU resources, which can slow down your PC. This article will guide you through simple steps to reduce high CPU usage caused by this process on Windows 11.

High CPU usage can affect your computer’s performance and make everyday tasks frustrating. Fortunately, there are several easy fixes you can try at home without needing technical expertise.

This guide starts with basic checks and moves towards more advanced solutions, ensuring you can follow along no matter your skill level. Let’s get started and help your PC run smoothly again.

By following these steps, you’ll understand why the issue happens and how to fix it effectively.

Quick Note Before You Begin

Before diving into the fixes, make sure your Windows 11 system is up to date. Sometimes, updates include performance improvements or bug fixes that can solve the problem automatically.

• Check that Windows Defender is enabled and working properly.
• Verify you are not running any other antivirus programs that might conflict with Windows Defender.
• Close all unnecessary applications to rule out other causes of high CPU usage.

Step 1: Restart Your Computer

Restarting your PC is the simplest step and can often fix temporary glitches causing high CPU usage. This refreshes system processes and clears memory.

How to restart:

1. Click the Start menu button.
2. Select the Power icon.
3. Choose “Restart”.

After rebooting, check if the Antimalware Service Executable still uses high CPU. If yes, continue to the next step.

Step 2: Schedule Windows Defender Scans

Windows Defender runs scans automatically, which can cause high CPU usage at inconvenient times. Scheduling scans during off-hours can help reduce interruptions.

How to schedule scans:

1. Press Win + R to open the Run dialog.
2. Type taskschd.msc and press Enter to open Task Scheduler.
3. In the left pane, navigate to Task Scheduler Library > Microsoft > Windows > Windows Defender.
4. Find the task named Windows Defender Scheduled Scan.
5. Right-click it and select Properties.
6. Go to the Triggers tab and click New.
7. Set the scan to run at a time when you’re not actively using your PC, like late at night.
8. Click OK to save.

Scheduling scans reduces chances of the Antimalware Service Executable running during your work hours.

Step 3: Add Antimalware Service Executable to Windows Defender Exclusions

Excluding the Antimalware Service Executable process from Windows Defender scans can help lower CPU usage. This stops Defender from scanning its own files repeatedly.

How to add exclusions:

1. Open Settings by pressing Win + I.
2. Go to Privacy & Security > Windows Security > Virus & Threat Protection.
3. Under Virus & Threat Protection Settings, click on Manage Settings.
4. Scroll down and select Add or remove exclusions.
5. Click Add an exclusion and choose Process.
6. Type MsMpEng.exe and confirm.

This tells Windows Defender not to scan its own executable, which can reduce CPU usage.

Step 4: Limit CPU Usage for Windows Defender via Group Policy

If you are comfortable using advanced Windows tools, you can limit the CPU resources Windows Defender uses during scans.

How to limit CPU usage:

1. Press Win + R and type gpedit.msc, then press Enter to open the Local Group Policy Editor.
2. Navigate to Computer Configuration > Administrative Templates > Windows Components > Microsoft Defender Antivirus > Scan.
3. Find the setting called Specify the maximum percentage of CPU utilization during a scan.
4. Double-click the setting and select Enabled.
5. Set the CPU percentage limit to a lower value, such as 30%.
6. Click Apply and then OK.

This limits how much CPU Defender can use, helping keep your system responsive.

Step 5: Disable Windows Defender Temporarily (Not Recommended)

If none of the above steps help and you need immediate relief, you can temporarily disable Windows Defender. However, this leaves your system vulnerable to threats, so use caution.

How to disable Windows Defender temporarily:

1. Open Settings by pressing Win + I.
2. Go to Privacy & Security > Windows Security > Virus & Threat Protection.
3. Click on Manage Settings under Virus & Threat Protection Settings.
4. Turn off Real-time protection.

Remember to turn it back on as soon as possible to keep your PC protected.

Alternative Methods and Advanced Options

If you are comfortable with command line tools, you can use PowerShell to tweak Defender settings or check for malware that might be causing excessive CPU usage.

Additionally, sometimes third-party antivirus software can conflict with Windows Defender, causing high CPU. Consider temporarily disabling or uninstalling any other antivirus to see if the problem improves.

Frequently Asked Questions (FAQs)

What is Antimalware Service Executable?

It is a background process for Windows Defender that scans your system for malware and other security threats.

Is it safe to disable Antimalware Service Executable?

Disabling it is not recommended because it leaves your computer unprotected from viruses and malware.

Why does Antimalware Service Executable use so much CPU?

High CPU usage usually happens during system scans or updates. Sometimes, it can be caused by conflicts or malware infections.

Can I replace Windows Defender with another antivirus?

Yes, but ensure the new antivirus is reputable and properly installed. Having multiple antivirus programs active simultaneously can cause conflicts and high CPU usage.

Will updating Windows fix this issue?

Often, yes. Microsoft releases fixes and improvements that can reduce CPU usage by Windows Defender.

When Nothing Works

If you’ve tried all the steps and still face high CPU usage, consider the following options:

• Run a full malware scan using a trusted third-party antivirus to rule out infections.
• Use the Windows Security Troubleshooter found in Settings under Troubleshoot.
• Reset Windows Defender settings to default using PowerShell commands (Set-MpPreference -DisableRealtimeMonitoring $false).
• Contact Microsoft Support or visit the official Microsoft Support website for advanced help.

Conclusion

High CPU usage by Antimalware Service Executable can be frustrating but is often fixable with simple steps. Starting with a basic restart, scheduling scans, and adding exclusions usually helps reduce the problem. Advanced users can limit CPU usage through Group Policy or PowerShell.

Always remember that Windows Defender plays a vital role in keeping your PC safe, so avoid disabling it permanently. Regular updates and scans ensure your system stays protected without slowing down your work.

By following this step-by-step guide, you can improve your Windows 11 PC’s performance while maintaining strong security.