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Sysmon is a powerful tool used for monitoring system activity on Windows computers. However, some users have experienced memory leaks when running Sysmon on Windows 11. This can cause the system to slow down or become unstable over time.

Fixing a memory leak in Sysmon requires a careful approach to ensure your system remains stable while the issue is resolved. Fortunately, there are several straightforward steps you can take to address this problem.

This guide will walk you through a step-by-step process to identify and fix Sysmon memory leaks on Windows 11. Each step is explained clearly, even if you have little technical experience.

By following these instructions, you can improve your system’s performance and keep Sysmon running smoothly.

Quick Note Before You Begin

Before starting the troubleshooting process, make sure you have administrator access to your Windows 11 PC. This is essential because many steps require changes to system files or services.

Also, ensure that your Windows 11 installation is up to date. Sometimes, Microsoft releases fixes that can improve system stability and compatibility with tools like Sysmon.

Check which version of Sysmon you currently have installed. Older versions may contain bugs that cause memory leaks.

Finally, back up any important data before making changes to system settings or configurations. This precaution helps protect your files in case something goes wrong.

Step 1: Verify Your Sysmon Version

Memory leaks can often be tied to specific versions of software. To check your current Sysmon version, open Command Prompt with administrator privileges and enter:

sysmon -c

This command will display your Sysmon configuration and version information.

If your version is outdated, it is important to update to the latest release, as newer versions often include bug fixes that can resolve memory leaks.

Step 2: Update Sysmon to the Latest Version

Visit the official Microsoft Sysinternals website to download the most recent Sysmon version. Here’s how:

• Go to Microsoft Sysmon Download Page.
• Download the latest Sysmon ZIP file.
• Extract the ZIP contents to a folder on your PC.
• Open Command Prompt as Administrator.
• Navigate to the extracted folder using cd command.
• Run the command to update Sysmon:

sysmon -u

This uninstalls the current version.

sysmon -i -accepteula

This installs the latest version with the default configuration.

Updating Sysmon ensures you have the latest fixes and improvements, which often address performance issues like memory leaks.

Step 3: Optimize Your Sysmon Configuration

Sysmon’s configuration files control which events are monitored. A very verbose or improperly configured file can cause excessive memory use.

To optimize:

• Review your current Sysmon XML configuration file.
• Remove unnecessary event types that you do not need to track.
• Use filters to limit event collection to relevant sources.

By reducing the number of events Sysmon monitors, you lower the memory requirements and decrease the chance of leaks.

If you don’t have a custom configuration, consider using a well-maintained, minimal configuration available online. For example, SwiftOnSecurity’s Sysmon Config is a popular choice.

Step 4: Restart Sysmon Service

Sometimes, restarting the Sysmon service can help clear temporary memory issues. Here’s how to restart the service:

• Open Command Prompt as Administrator.
• Stop the service using:

sc stop sysmon64

• Start the service again:

sc start sysmon64

Alternatively, you can restart your computer if you prefer a full system reboot.

Step 5: Monitor Memory Usage

After performing the previous steps, it’s important to monitor Sysmon’s memory usage to confirm the leak is fixed.

• Open Task Manager by pressing Ctrl + Shift + Esc.
• Find Sysmon64.exe in the Processes tab.
• Observe its memory usage over time.

Memory usage should stabilize and not continuously grow. If it still grows steadily, further troubleshooting may be needed.

Alternative Method: Use Windows Event Forwarding Instead

If fixing the memory leak in Sysmon proves difficult, you might consider reducing your reliance on Sysmon by using Windows Event Forwarding (WEF). WEF collects and forwards Windows event logs across computers and can sometimes serve as a lighter alternative.

This approach requires configuring event subscriptions and forwarding settings but can lessen the need for heavy monitoring tools like Sysmon.

Frequently Asked Questions (FAQs)

Why does Sysmon cause a memory leak on Windows 11?

Memory leaks often result from bugs in older Sysmon versions or overly complex configurations that cause the program to consume more memory than intended.

Can I fix the memory leak without updating Sysmon?

Sometimes optimizing the configuration or restarting the service can help, but updating is the most reliable fix since it includes bug patches.

Is it safe to uninstall and reinstall Sysmon?

Yes, uninstalling and reinstalling Sysmon is safe when done correctly. Always run commands with administrator privileges and back up your configuration files.

How often should I update Sysmon?

Check for updates periodically, especially if you encounter issues. Updating every few months or when notified of new releases is a good practice.

Will disabling some event types affect my system security?

Reducing event monitoring can lower system visibility but may be necessary to maintain performance. Choose the most relevant events to balance security and resource use.

When Nothing Works

If after trying all the steps your Sysmon memory leak persists, consider these final options:

• Visit the official Microsoft Sysmon documentation for advanced troubleshooting tips.
• Search or ask for help on forums like Stack Overflow or Microsoft Tech Community.
• Use Windows Performance Toolkit or Resource Monitor to diagnose the memory usage in greater detail.
• Consider temporarily disabling Sysmon if it severely impacts system performance until a fix is available.

Conclusion

Memory leaks in Sysmon on Windows 11 can cause frustrating performance issues, but they are often fixable with simple steps. Always start by verifying your Sysmon version and updating to the latest release.

Optimizing your Sysmon configuration helps reduce unnecessary resource use, while restarting the service can clear temporary memory problems. Regular monitoring ensures your fixes are effective.

If these steps don’t resolve the issue, alternative methods like Windows Event Forwarding or seeking help from official resources can provide further assistance.

Following this guide will help you maintain a stable and efficient system while benefiting from Sysmon’s powerful monitoring capabilities.