How to fix MsMpEng.exe High CPU Usage problem

Last updated on July 25th, 2019

In my opinion, Microsoft Security Essentials is a well working free Antivirus solution for individuals and small business. But some times, on different computers, I have discovered that Microsoft Security Essentials (MSE) Antimalware service “MsMpEng.exe” causes high CPU usage with no obvious reason. 

After resolving many times this problem, I discovered that the “MsMpEng.exe” high CPU usage problem may happen for various reasons so there is not only one solution to solve it. For example, in the past I have solved the “MsMpEng.exe” high CPU usage problem just by cleaning an infected computer from a nasty virus, or by uninstalling and reinstalling MSE again or by removing an incompatible with MSE security program, etc.


If you want to resolve the MsMpEng.exe high CPU usage problem, then try the following solutions:

How to fix MsMpEng.exe high CPU usage problem.


1. Before continuing to resolve the "MsMpEng.exe" high CPU usage problem, first make sure that you haven't installed another antivirus program on your computer.
2. if you have Windows XP then you must uninstall Microsoft Security Essentials because is no longer supported in Windows XP.

Solution 1: Check and Clean your computer from Malware.

Solution 2: Uninstall & Re-install Microsoft Security Essentials.

Solution 3: Exclude "MsMpEng.exe" file from scanning.

Solution 4. Re-Schedule MSE scanning time – Disable Microsoft Security Client.

Solution 5: Install another antivirus program on your computer.

Solution 1: Check your computer for Malware.

Step 1. Start your computer in Safe Mode with Networking.

In order to check your computer for possible Malware programs running on it, it is better to start your computer in Safe mode with network support. To do that:

Windows 7, Vista & XP users:

  1. Close all programs and reboot your computer.
  2. Press the "F8" key as your computer is booting up, before the appearance of the Windows logo.
  3. When the "Windows Advanced Options Menu" appears on your screen, use your keyboard arrows keys to highlight the “Safe Mode with Networking” option and then press "ENTER".


Windows 8 & 8.1 users:

  1. Press “Windowsimage_thumb5_thumb  + “R” keys to load the Run dialog box.
  2. Type “msconfig” and press Enter.
  3. Click the Boot tab and check “Safe Boot” & “Network”.
  4. Click “OK” and restart your computer.

Note: In order to boot Windows in “Normal Mode” again, you have to uncheck the “Safe Boot” setting by using the same procedure.


Step 2. Check & terminate possible malicious processes with RogueKiller.

1. Download and save "RogueKiller" utility on your computer'* (e.g. your Desktop)

Notice*: Download version x86 or X64 according to your operating system's version. To find your operating system's version, "Right Click" on your computer icon, choose "Properties" and look at "System Type" section.


2. Double Click to run RogueKiller.

3. Let the prescan to complete and then press on "Scan" button to perform a full scan.


3. When the full scan is completed, press the "Delete" button to remove all malicious items found.


Step 3: Remove Adware programs with AdwCleaner.

1. Download and save “AdwCleaner” utility to your desktop.


2. Close all open programs and Double Click to open ”AdwCleaner” from your desktop.

3. Press “Scan”.


4. When the scan is completed, press “Clean” to remove all the unwanted malicious entries.


4. Press “OK” at “AdwCleaner – Information” and press “OK” again to restart your computer.


5. When your computer restarts, close "AdwCleaner" information (readme) window and continue to the next step.

Step 4. Remove Malware with Malwarebytes Anti-Malware Free.

Download and install one of the most reliable FREE anti malware programs today to clean your computer from remaining malicious threats. If you want to stay constantly protected from malware threats, existing and future ones, we recommend that you install Malwarebytes Anti-Malware Premium:

Malwarebytes™ Protection
Removes Spyware, Adware & Malware.
Start Your Free Download Now!

Quick download & Installation instructions:

  • After you click the above link, press at the “Start My Free 14-Trial” option to start your download.


  • To install the FREE version of this amazing product, uncheck the “Enable free Trial of Malwarebytes Anti-Malware Premium” option at the last installation screen.


Scan & Clean your computer with Malwarebytes Anti-Malware.

1. Run "Malwarebytes Anti-Malware" and allow the program to update to its latest version and malicious database if needed.


2. When the update process is completed, press the “Scan Now” button to start scanning your system for malware and unwanted programs.


3. Now wait until Malwarebytes Anti-Malware finishes scanning your computer for malware.


4. When the scan has completed, first press the “Quarantine All” button to remove all threats and then click “Apply Actions”.


5. Wait until Malwarebytes Anti-Malware removes all infections from your system and then restart your computer (if required from the program) to completely remove all active threats.


6. After the system restarts, run Malwarebytes' Anti-Malware again to verify that no other threats remain in your system.

Now check if “MsMpEng.exe” high CPU usage problem is gone, otherwise continue to the rest of this article.

Solution 2: Uninstall and Re-install Microsoft Security Essentials.

Step 1. Uninstall Microsoft Security Essentials from your Control panel.

1. To do this, go to:

  • Windows 7 & Vista: Start > Control Panel.
  • Windows XP: Start > Settings > Control Panel


  • Windows 8 & 8.1:
  1. Press “Windows”  Image-201_thumb8  + “R” keys to load the Run dialog box.
  2. Type “control panel” and press Enter.

2. Double click to open:

  •  Add or Remove Programs if you have Windows XP
  • Programs and Features if you have Windows 8, 7 or Vista.


3. In the program list, find and Remove (Uninstall) the “Microsoft Security Essentials” application.

Note: If you are having problems removing Microsoft Security Essentials by using the “Add/Remove Programs” feature, then you have to download and run the MSE removal utility. (MS Article ID: 2483120).


4. After removing Microsoft Security Essentials restart your computer.

Note: After the restart, make sure that MSE application is not listed anymore on the installed programs.

Step 2: Reinstall Microsoft Security Essentials.

After the computer restarts, go to Microsoft Security Essentials download site to download and install MSE on your computer again.

Solution 3: Exclude “MsMpEng.exe” from scanning

1. Open Microsoft Security Essentials main application and click “Settings”.


2. Click “Excluded files and locations” on the left pane.


3. Click “Browse”.


4. Navigate to the following location to select the “MsMpEng.exe” file and press “OK”.

Windows 7, Vista & XP users: C:\Program Files\Microsoft Security Client\MsMpEng.exe

Windows 8 users: C:\Program Files\Windows Defender\MsMpEng.exe


5. Press “Add”.


6. Press “Save Settings”.


7. Reboot your computer.

Solution 4. Re-Schedule MSE scanning time or Disable Real-Time Protection.

Step 1. Re-Schedule Microsoft Security Essentials Scanning times

One useful feature of MSE is the automatic scanning for virus risks at specific days and hours. So find out at what hours the scanning is performed and set a scan time that is not interrupting your work (e.g. late night hours).

To schedule the Microsoft Security Essentials scanning time:

1. Open Microsoft Security Essentials main application and click “Settings”.

2. Click at “Scheduled Scan” at the left pane.


3. Set a different day & time for the scheduled scan and then press “Save Changes”.


4. Close MSE main application.

Now check if the “MsMpEng.exe” high CPU usage problem still persists. If yes, then temporarily disable the MSE real-time protection to find out if this feature causes the high CPU usage problem.

Step 2. Disable Microsoft Security Essentials Real-time protection.

To disable Microsoft Security Essentials Real-Time protection:

1. Open Microsoft Security Essentials main application and click “Settings”.

2. Click “Real-time protection” at the left pane.


3. Uncheck the box next to “Turn on real-time protection (recommended)” and then press “Save changes”.


4. Close “Microsoft Security Essentials”.

If the “MsMpEng.exe” high CPU usage problem still persists, then continue to the next step and prevent the “Microsoft Security Client” from being loaded at Windows startup.

Step 3. Disable Microsoft Security Client from starting up.

To disable “Microsoft Security Client” from startup:

1. Press “Windows”  Image-201_thumb8  + “R” keys to load the Run dialog box.

2. Type “msconfig” and press Enter.


3. Click the “Startup” tab.


4. Uncheck the box next to “Microsoft Security Client” entry” and press “OK


5. Restart your computer.

After the restart, check if your computer is working smoothly and “MsMpEng.exe” high CPU usage problem is gone. Then uninstall Microsoft Security Essentials and install another antivirus program on your computer. (Solution 5).

Solution 5: Install another antivirus program on your computer.

If you are still having problems with Microsoft Security Essentials, then you can try to use another antivirus to protect your computer from risks. To do that:

Step 1. Uninstall Microsoft Security Essentials from your computer.

First of all completely uninstall MSE from your computer by using the instructions of “Solution 2 – Step 1“ of this post.

Step 2. Install a different antivirus program in your computer.

After you uninstall MSE from your computer, proceed to install a different antivirus security program to protect your computer. Suggested free antivirus programs for this task: Avira’s Antivir Free Antivirus, Avast Free Antivirus  or AVG Antivirus Free.

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