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How to Fix Microsoft Common Language Runtime Native Compiler High CPU Usage on Windows 11

Microsoft Common Language Runtime Native Compiler (also known as Native Image Generator or NGEN) is a system process designed to improve the performance of .NET applications. Sometimes, users notice that this process causes high CPU usage on Windows 11, which can slow down the computer and affect overall performance.

This article will guide you through simple, step-by-step solutions to fix high CPU usage caused by the Native Compiler. Each step is explained in a clear and basic way, so even beginners can follow along easily.

By the end, you will understand why this problem happens and how to resolve it effectively. Let’s get started with some quick notes before diving into the fixes.

These instructions work with Windows 11 and apply to most versions of the operating system.

Quick Note

  • Make sure your Windows 11 system is up to date with the latest updates from Microsoft.
  • Check if you have any antivirus or security software running that might interfere with system processes.
  • Close all unnecessary applications before troubleshooting to get accurate results.
  • It’s helpful to have basic administrator privileges on your PC to perform some of the steps below.

Step 1: Restart Your Computer

Sometimes, the simplest solution is the best. Restarting your computer can clear temporary issues that cause high CPU usage.

Why this helps: Restarting stops all running processes and clears the memory, which can fix temporary glitches affecting the Native Compiler.

Step 2: Check for Windows Updates

Keeping Windows updated ensures you have the latest fixes and improvements that might solve performance problems.

  1. Click the Start button and open Settings.
  2. Select Windows Update on the left sidebar.
  3. Click Check for updates.
  4. If updates are available, click Download and install.
  5. After updates finish, restart your PC.

Why this helps: Microsoft regularly releases patches that fix bugs and performance issues related to system processes like the Native Compiler.

Step 3: Scan for Malware

Malware or viruses can disguise themselves as system processes and cause high CPU usage.

  1. Open Windows Security by typing it in the Start menu.
  2. Click on Virus & threat protection.
  3. Select Quick scan or Full scan for a thorough check.
  4. Follow any instructions if threats are detected.

Why this helps: Removing malware ensures that the CPU usage is not caused by malicious software pretending to be the Native Compiler.

Step 4: Disable Native Image Generation Service Temporarily

If high CPU usage continues, you can try disabling the Native Image Generator service temporarily to see if it stops the problem.

  1. Press Windows + R to open the Run dialog box.
  2. Type services.msc and press Enter.
  3. In the Services window, scroll to find .NET Runtime Optimization Service.
  4. Right-click on it and select Stop.
  5. Check if CPU usage drops.

Important: This service helps improve app performance, so do not leave it disabled permanently. Only keep it off temporarily while troubleshooting.

Step 5: Reset the Native Image Cache

The Native Image Generator creates cached files to speed up apps. Sometimes, this cache can get corrupted and cause high CPU usage.

  1. Open Command Prompt as an administrator. To do this, type cmd in the Start menu, right-click on it, and select Run as administrator.
  2. In the Command Prompt window, type the following command and press Enter:
ngen.exe executequeueditems

This command forces the Native Image Generator to process any pending tasks and rebuild the cache.

After running the command, restart your PC and check if the CPU usage improves.

Step 6: Use System File Checker to Repair Corrupted Files

Corrupted system files can cause the Native Compiler to behave abnormally.

  1. Open Command Prompt as administrator.
  2. Type the following command and press Enter:
sfc /scannow

This will scan and repair corrupted system files automatically. The process can take some time, so be patient.

After it completes, restart your PC and observe the CPU usage.

Alternative Method: Disable Native Image Generation via Registry Editor (Advanced)

If you are comfortable editing the Windows Registry, you can disable the Native Image Generator permanently. However, this is not recommended unless other methods fail, as it may affect system performance.

  1. Press Windows + R, type regedit, and press Enter.
  2. Navigate to the following key:
    3. HKEY_LOCAL_MACHINESOFTWAREMicrosoft.NETFramework
  3. Look for a DWORD value named UseNGen. If it doesn’t exist, create it by right-clicking and selecting New > DWORD (32-bit) Value.
  4. Set the value of UseNGen to 0 to disable Native Image Generation.
  5. Close Registry Editor and restart your PC.

Warning: Making incorrect changes in the Registry can cause serious system issues. Always back up your Registry before making changes.

Frequently Asked Questions (FAQs)

What is the Microsoft Common Language Runtime Native Compiler?

It is a Windows service that precompiles .NET applications to improve their startup times and overall performance.

Is it safe to disable the Native Compiler service?

You can disable it temporarily for troubleshooting, but it is not recommended to keep it disabled permanently, as it may slow down .NET applications.

Why does the Native Compiler cause high CPU usage?

High CPU usage can occur if the service is stuck processing cached files, if the cache is corrupted, or if malware is impersonating the process.

How can I tell if the high CPU usage is caused by malware?

Running a full malware scan is the best way to confirm. You can also check the process location in Task Manager to ensure it points to the legitimate system folder.

Will updating Windows fix this issue?

Often, yes. Microsoft regularly releases patches that improve system services and fix bugs that might cause high CPU usage.

When Nothing Works

If you have tried all the steps above and still experience high CPU usage by the Native Compiler, consider the following:

  • Perform a System Restore to a point before the problem started.
  • Use the Windows Reset feature to reinstall the operating system without losing personal files.
  • Visit the official Microsoft support page for detailed assistance: Microsoft Support.
  • Seek help from professional technicians if you are uncomfortable performing advanced troubleshooting.

Conclusion

High CPU usage caused by the Microsoft Common Language Runtime Native Compiler can be frustrating, but it is usually fixable with simple steps. Starting from restarting your PC, checking for updates, and scanning for malware, to more advanced options like resetting the native image cache or repairing system files—all these methods help restore your system’s performance.

Remember to proceed carefully, especially when making changes to system services or the Windows Registry. Following this guide will help you identify the cause and resolve the issue effectively, ensuring your Windows 11 PC runs smoothly again.

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