dllhost.exe COM Surrogate High CPU/Memory Usage (Fix)

Published by Nyau Wai Hoe - Updated on

COM Surrogate, technically recognized as dllhost.exe, is one of the intrinsic processes you may encounter when navigating the Task Manager on a Windows-based computer. It should not be dismissed as a mere background task, as this process plays a significant role in the smooth operation of numerous applications. In certain instances, users have reported encountering issues such as unusually high CPU or memory usage associated with this process, especially in Windows 11 and Windows 10.

It’s crucial to gain an understanding of what dllhost.exe is, its relationship with the Component Object Model (COM), and how to address potential issues stemming from it. This includes the ability to distinguish genuine processes from potentially malicious entities that may attempt to masquerade as the COM Surrogate. In this article, we will get into the details of dllhost.exe, guiding you through its importance, troubleshooting steps, and protective measures.

dllhost.exe COM Surrogate High CPU Memory Usage

What exactly is dllhost.exe (COM Surrogate)?

The COM Surrogate (dllhost.exe) is a Windows system process that is, more often than not, harmless and operates discreetly in the background. To understand its role, we need to break down its name:

  1. dllhost.exe: This stands for “Dynamic Link Library Host“. Dynamic Link Libraries (DLLs) are external parts of applications that run on Windows and other operating systems. These libraries are essential because they contain code, data, and resources that multiple programs can utilize simultaneously without having to have multiple copies running. The dllhost.exe is essentially a shell process to run these DLLs outside of the original application.
  2. COM Surrogate: COM stands for “Component Object Model“. It’s a Microsoft technology that allows developers to create “COM objects” as part of their software. These objects can be used by other applications. The “Surrogate” part refers to the act of this process running in the place of another process. So, COM Surrogate is essentially a process that runs a COM object outside of its original process.

What is dllhost.exe COM Surrogate

In simpler terms, COM Surrogate (dllhost.exe) is a process that acts as a “middleman”, allowing your system to interact with DLL files or COM objects that might be otherwise inaccessible or might cause the parent application to crash if there was a problem. For instance, when you’re viewing thumbnails of images or videos in Windows File Explorer, the COM Surrogate process is used to protect the File Explorer from crashing if it encounters a corrupted file. Instead, if there’s an issue, the COM Surrogate would crash, leaving your File Explorer unharmed.

Also see: How to Limit CPU Usage of a Process in Windows 11

Why does dllhost.exe COM Surrogate cause high CPU and memory usage?

In an ideal scenario, the dllhost.exe COM Surrogate process should operate discreetly without hogging system resources. However, there are instances when users report unusually high CPU or memory usage associated with this process. The reasons behind this can vary, and understanding these triggers can provide clarity on the steps needed for resolution.

Dependent applications and processes

Every time a certain application uses a COM object or DLL, the dllhost.exe COM Surrogate may be invoked to facilitate this interaction. Some third-party applications or even specific Windows functions might excessively utilize these objects, leading to an increased load on the COM Surrogate process. It’s not always the COM Surrogate’s fault; the parent application might be misusing or overusing certain resources. Multimedia applications, video editors, or even specific versions of web browsers can be culprits.

Useful guide: How to Know Which Process is Using a File in Windows 11

Corrupted files or thumbnails

As mentioned earlier, when you browse folders containing multimedia files like images or videos, the dllhost.exe COM Surrogate helps in generating thumbnails. If any of these files are corrupted, it can cause the COM Surrogate process to consume an inordinate amount of system resources trying to read or process the damaged file. This endless loop can result in a spike in both CPU and memory usage. Such scenarios are relatively common.

See also: How to Stop Windows 11 from Showing Thumbnail Preview

Windows 11 Files and Folders Thumbnails Icons

Malware or virus infection

While the genuine dllhost.exe COM Surrogate process is entirely safe, some malware or viruses cleverly disguise themselves using familiar-sounding process names to avoid detection. If this process is consistently consuming high system resources without a discernible reason, it might be a rogue process, and not the genuine COM Surrogate.

Pro tip: How to Scan an .exe File for Viruses to Check If It’s Safe

How to identify which subprocess or application is using the problem COM

When the dllhost.exe COM Surrogate process exhibits high resource usage, it’s essential to pinpoint the exact cause. A tool like Process Explorer can be invaluable in this endeavor. Here’s a step-by-step guide to using Process Explorer for this purpose:

  1. If you don’t have it already, download Process Explorer from the official Microsoft website. Once downloaded, run the application.Process Explorer for Windows 11
  2. In the Process Explorer window, you’ll see a list of running processes. Look for dllhost.exe or COM Surrogate. There might be multiple instances running, so ensure you identify the one consuming high resources.
  3. Simply hover your mouse over the dllhost.exe entry. A tooltip will appear, providing brief information about the subprocess or application using the COM. For example, if the tooltip indicates “Microsoft Thumbnail Cache,” the File Explorer thumbnail generation could be the primary cause of the resource spike.COM Surrogate dllhost.exe high cpu memory usage in Windows 11 10
  4. For a more detailed examination, right-click on the high-resource dllhost.exe process and select “Properties”.dllhost.exe properties
  5. In the Properties window, go to the “Threads” tab. Here, you’ll see a list of all the DLLs (Dynamic Link Libraries) being used by that particular COM Surrogate process.dllhost.exe what is it
  6. Analyze the listed threads. The thread consuming the highest CPU will usually be the one causing the problem. Note down the DLL name.
  7. With the problematic DLL identified, you can now search online for more information about it. This will give you insights into which application or service it is associated with.

Related concern: Why is My Memory Usage So High When Nothing is Running?

Manage the identified application

If you’ve determined that a specific application or subprocess is the cause, you can decide what to do next.

  1. Update or reinstall the application: Often, issues arise due to outdated software. Check if there’s an updated version available and install it. If you’re already using the latest version, consider reinstalling it to rectify any potential corruption.
  2. Disable the application: If the problem persists, and you believe a particular application is the culprit, consider disabling it temporarily to check if the high resource usage subsides.
  3. Seek alternatives: If a specific application continuously causes issues, it might be worth looking into alternative software that performs the same function but is more optimized.

Scan your computer for malware first

Before making any significant changes to your system settings or software, it’s crucial to rule out the possibility that the high resource usage is due to malware or a virus. Malicious software can often mimic or exploit legitimate processes like dllhost.exe COM Surrogate.

  1. Open your antivirus software: Ensure that you have a reputable antivirus program installed on your computer. If you don’t, consider using the built-in Microsoft Defender available in Windows 11 and 10.
  2. Run a complete system scan: Once your antivirus is active, initiate a full system scan. This comprehensive check will take longer than a quick scan but is thorough in searching for potential threats.dllhost.exe COM Surrogate Virus
  3. Check results and quarantine threats: If the antivirus detects any threats, follow the software’s recommendations, which typically involve quarantining or removing the malicious files.
  4. Regularly update your antivirus: Keep your antivirus definitions up-to-date. Regular updates will ensure that your system is protected against the latest threats.

Related resource: How to remove a known virus using CMD in Windows 11 or 10

Disabling thumbnail generation

Another common culprit behind the high resource usage by dllhost.exe COM Surrogate is the generation of thumbnails, especially if there are corrupted multimedia files. Disabling thumbnail viewing in File Explorer has proven effective for many users who have observed high CPU and memory usage by dllhost.exe.

  1. Click on the File Explorer icon in the taskbar or press Win + E on your keyboard.
  2. Within File Explorer, click on the three-dot menu icon in the upper-right corner, then choose “Options” from the dropdown.File Explorer Folder Options
  3. In the Folder Options window, switch to the “View” tab.
  4. In the list of advanced settings, look for the option labeled “Always show icons, never thumbnails” and check this option.dllhost.exe COM Surrogate System Error
  5. Click on “Apply“, followed by “OK” to confirm the changes.
  6. Restart your computer for the changes to take full effect and check if the issue with dllhost.exe COM Surrogate is resolved.

Running System File Check (SFC)

System File Check (SFC) is a built-in Windows utility that can find and repair corrupted or missing system files, which might be causing the dllhost.exe COM Surrogate process to misbehave.

  1. Open Command Prompt as administrator: Press the Windows key, type “cmd”, right-click on “Command Prompt”, and choose “Run as administrator”.
  2. Initiate the SFC scan: In the Command Prompt window, type sfc /scannow and press Enter.
  3. Wait for the scan to complete: The SFC scan can take some time. Once completed, follow any on-screen instructions to address detected issues.

SFC scannow successful repair Windows 11

Should you interfere with the dllhost.exe COM Surrogate process?

The dllhost.exe COM Surrogate is a fundamental part of the Windows ecosystem. However, knowing when and how to intervene when it’s causing issues can be tricky. Here’s some guidance:

The importance of not acting rashly

Resist the temptation to end the dllhost.exe COM Surrogate process abruptly via Task Manager or any other method. Terminating this process can lead to unexpected system behaviors, application crashes, or even data loss.

Waiting out temporary high resource usage scenarios

Sometimes, the high CPU or memory usage is temporary, especially if the process is handling a large set of multimedia files or performing a complex task. In such cases, patience is the best approach. Wait for a bit and monitor to see if the resource consumption decreases on its own.

Ensuring the process’s legitimacy before taking action

Always verify that the process you’re observing is the legitimate dllhost.exe COM Surrogate. Malware often disguises itself as legitimate processes. If you’re uncertain, run a malware scan, as discussed in earlier sections.

Seeking professional help when in doubt

If you’re unsure about any step or the nature of the problem, consult with a professional or seek guidance from specialized forums or tech communities such as Reddit and Microsoft forums. It’s always better to be cautious than to risk compromising your system’s stability.

Run Windows Update if you haven’t already

Keeping your Windows OS updated is a proactive measure to ensure that all known bugs or vulnerabilities are addressed.

  1. Press the Windows key and click on “Settings”.
  2. Select “Windows Update” on the left pane.
  3. Click on “Check for updates”.Check for Windows Update
  4. If updates are available, click “Download” or “Install now”. Ensure you save any ongoing work as the update process might require a restart.


The dllhost.exe COM Surrogate process plays an important role in the Windows architecture, ensuring that COM objects are executed safely and efficiently. While it’s generally a silent and safe worker, occasional issues can cause resource-intensive behaviors. By following the steps outlined in this article, you can diagnose and identify the root causes and implement solutions to resolve its high resource usage problem. Always remember: act with caution, keep your system updated, and seek expert advice when in doubt.

Nyau Wai Hoe
Nyau Wai Hoe is the Founder and Chief Editor of WindowsDigitals.com. With a degree in software engineering and over 12 years of experience in the tech support industry, Nyau has established himself as an expert in the field, with a primary focus on the Microsoft Windows operating system. As a tech enthusiast, he loves exploring new technologies and leveraging them to solve real-life problems.

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