How to Resolve High CPU Usage by Antimalware Service Executable (MsMpEng) – 2025

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

Antimalware Service Executable (MsMpEng.exe) is a core process of Windows Defender, designed to protect your computer from malware threats. However, it often causes high CPU, memory, and disk usage, slowing down your system significantly. If you’re experiencing performance issues due to MsMpEng, this guide will provide effective solutions to fix the problem.

WHY DOES ANTIMALWARE SERVICE EXECUTABLE USE HIGH CPU?

Before fixing the issue, it’s essential to understand why MsMpEng consumes excessive CPU and memory:

• Real-time Protection – Constantly scans files, connections, and programs for threats.
• Full Scan Activity – Periodic deep scans can use a lot of system resources.
• Conflicts with Other Antivirus Software – Running multiple antivirus programs can cause performance issues.
• Corrupt Windows Defender Files – Corrupt or outdated definitions can lead to abnormal resource usage.
• Excessive File Scanning – Windows Defender scans its own files, leading to CPU spikes.

METHOD 1: LIMIT WINDOWS DEFENDER’S CPU USAGE

You can restrict the amount of CPU Windows Defender can use by using a command in PowerShell:

1. Press Win + X and select Windows Terminal (Admin).
2. Type the following command and press Enter:

   Set-MpPreference -ScanAvgCPULoadFactor 30
   
   

3. This limits the CPU usage to 30%. You can adjust the value as needed.

METHOD 2: SCHEDULE WINDOWS DEFENDER SCANS TO AVOID HIGH USAGE

Since real-time protection and scheduled scans consume a lot of resources, changing the scan schedule can help:

1. Press Win + R, type taskschd.msc, and hit Enter to open Task Scheduler.
2. Navigate to Task Scheduler Library > Microsoft > Windows > Windows Defender.
3. Locate Windows Defender Scheduled Scan, right-click it, and select Properties.
4. Under the Triggers tab, modify the schedule to run during low-usage hours.
5. Click OK to save changes.

METHOD 3: EXCLUDE WINDOWS DEFENDER FROM SCANNING ITS OWN FILES

To prevent Windows Defender from scanning its own files, add an exclusion:

1. Press Win + I to open Settings.
2. Go to Update & Security > Windows Security > Virus & threat protection.
3. Click Manage settings under Virus & threat protection settings.
4. Scroll down and click Add or remove exclusions.
5. Click Add an exclusion, choose Folder, and navigate to C:\Program Files\Windows Defender.
6. Click Select Folder to confirm.

METHOD 4: TURN OFF WINDOWS DEFENDER (TEMPORARY SOLUTION)

Disabling Windows Defender can resolve high CPU usage, but it’s recommended to use an alternative antivirus:

1. Press Win + R, type gpedit.msc, and hit Enter.
2. Navigate to Computer Configuration > Administrative Templates > Windows Components > Microsoft Defender Antivirus.
3. Double-click Turn off Microsoft Defender Antivirus, select Enabled, and click OK.
4. Restart your computer for changes to take effect.

To re-enable Windows Defender, repeat the steps and set it to Not Configured.

METHOD 5: DISABLE WINDOWS DEFENDER REAL-TIME PROTECTION

If you don’t want to disable Windows Defender completely, turning off real-time protection can help:

1. Press Win + I to open Settings.
2. Navigate to Update & Security > Windows Security > Virus & threat protection.
3. Under Virus & threat protection settings, click Manage settings.
4. Toggle off Real-time protection.

Note: Windows Defender will automatically turn real-time protection back on after a while.

METHOD 6: CHECK FOR WINDOWS UPDATES

Microsoft regularly releases updates to fix performance issues. Updating Windows can resolve high CPU usage:

1. Press Win + I to open Settings.
2. Click Update & Security, then Windows Update.
3. Click Check for updates and install any available updates.

METHOD 7: PERFORM A CLEAN BOOT

A clean boot starts Windows with only essential programs and services:

1. Press Win + R, type msconfig, and hit Enter.
2. Go to the Services tab and check Hide all Microsoft services.
3. Click Disable all, then go to the Startup tab and click Open Task Manager.
4. Disable all startup items and restart your computer.
5. Check if the high CPU usage issue persists.

METHOD 8: USE AN ALTERNATIVE ANTIVIRUS SOFTWARE

If Windows Defender continues to cause issues, consider using a lightweight third-party antivirus program like:

• Bitdefender
• Kaspersky
• Avast
• ESET NOD32

Before installing another antivirus, ensure Windows Defender is disabled to prevent conflicts.

METHOD 9: DELETE WINDOWS DEFENDER’S HISTORY FILES

Old or corrupt Windows Defender history files can cause performance issues:

1. Press Win + R, type the following, and hit Enter:

   C:\ProgramData\Microsoft\Windows Defender\Scans\History\Service

2. Delete all files inside the Service folder.
3. Restart your computer and check CPU usage.

FINAL THOUGHTS

Antimalware Service Executable (MsMpEng.exe) is essential for security but can sometimes slow down your computer. By following the methods above, you can reduce high CPU usage while keeping your system protected. If the issue persists, consider using alternative security software that consumes fewer resources.