What is COM Surrogate (dllhost.exe) and Why is it Running?

 March 6, 2022

By  Gregory

Whether it’s “COM Surrogate” processes that you have found running in Task Manager or the “COM Surrogate has stopped working” error abruptly pops up on your screen, we know what to do about it. 

The following article covers almost everything one should know about handling COM Surrogate in Windows. We have structured this guide in a format that makes it easy for anyone to understand and do what needs to be done for COM Surrogate processes and related errors.  

So without further ado, let’s get into it.

COM Surrogate (dllhost.exe) – A Newbie Friendly Explanation

If you inquire about the COM Surrogate processes in Task Manager, you will come to know they have the file name “dllhost.exe.” These processes don’t have any customized icons to them, making it even hard for the users to figure out what they are and the purpose they serve. 

To cut the chase, COM Surrogate is a part of the Windows operating system. You are more likely to find these processes in Windows 10, Windows 8, Windows 7, and even older versions of Windows. To understand what a COM surrogate process is and why it’s running on your PC, you must first know about COM objects. 

In simpler terms, Component Object Model (COM) is a mechanism that allows interaction between different applications and programming languages. It facilitates developers with an interface to create COM objects that plug with other programs and extend them. 

For example, in Windows File Manager, COM objects help create thumbnails for images, videos, and other files. However, the issue with COM objects is that if they crash, it will bring down the entire host process with it. To tackle this very problem, Microsoft comes with a solution in the name of COM Surrogate. 

In a nutshell, COM Surrogate is a sacrificial process for a COM object. It runs outside of the original process that requested it. So when a COM object crashes, it will only take down the COM Surrogate process instead of the original host process. 

For example, when File Manager requests a COM object to extract a thumbnail for a file, Windows will instantly shoot up a COM Surrogate process to host that COM object. This way, if the COM object crashes, it will only affect the COM Surrogate process, keeping the original process safe and intact. 

Is COM Surrogate a Virus?

A COM Surrogate process is a legitimate Windows process. However, it’s often suspected as a virus due to the malware programs using dllhost.exe (same filename as COM Surrogate processes) to mask their dirty agenda. It’s not uncommon for a virus to hide behind a COM Surrogate process. 

What you can do is open Task Manager and right-click on the COM Surrogate process, and choose “Open file location.” If it leads you to the C:\Windows\System32 folder, it has little to no chances of being a virus. In case it’s located in some other folder, you must run a full virus scan for your PC. 

Furthermore, if you find a large number of COM Surrogate processes taking up a significant amount of CPU usage, it’s likely to be caused by a malicious program. In such instances, you should immediately shoot up your antivirus and remove any suspected applications you come across.  

Can I Disable It?

As we know, COM Surrogate processes have an important role to play; you can’t disable it like other Task Manager processes. Although, there is no need for you to stop it. You can let it run and not be bothered by it as you do your thing. Moreover, you must understand that these processes are there for a reason. You won’t find them running in the first place if it wasn’t requested by Windows applications for an executable task.

How To Know Which COM Object a COM Surrogate Is Hosting?

It’s human nature to be curious and want to know what is not known. If you have an urge to figure out the COM object a COM Surrogate process is hosting, there is a way to it. 

For this, you have to download a specialized Microsoft tool called Process Explorer. Once installed, launch the app, and hover over to the dllhost.exe process, and you will have the required information available for you. 

How to Fix/Remove COM Surrogate in Windows?

COM Surrogate related problems can present themselves in a number of ways. Below we have discussed and provided solutions for some prevalent issues caused by COM Surrogate in Windows.

COM Surrogate Not Working 

“COM Surrogate has stopped working” is one of the most infamous errors among Windows users. It mainly takes place when you are trying to browse folders containing media files. Many users have also encountered it while printing a PDF or other file formats. 

The error can occur due to various reasons. However, they are not relevant when you have already got the error up on your screen. The only thing that matters is the ways to troubleshoot the problem. Implementing the following solutions will surely help you get rid of it. 

Fix 1: Rollback your Video Card Driver

  • Press Windows+R keys simultaneously and type “devmgmt.msc” in the Run dialog box as it appears. 
  • In the Device Manager window, expand the “Display adapters” option.
  • Right-click on your graphic card and select “Properties.”
  • At the top, click on the Driver tab, and then hit the “Roll Back Driver” option. 

NOTE: If Roll Back Driver isn’t clickable in your case, you can download the previous version driver for your video card using the manufacturer’s website. 

Fix 2: Add dllhost.exe to the DEP Exception

  • Type “control” in the Windows search bar, and open the Control Panel app as the results appear for the searched item.
  • Click on System and Security and choose System.
  • On the right panel, click on Advanced system settings.
  • Under the Performance option, tap on Settings
  • On the upper tab, click on Data Execution Prevention and choose Turn on DEP for all programs and services except those I select:
  • Next, click on Add and navigate to C:\Windows\System32\dllhost.exe if you have a 32-bit system and C:\Windows\SysWOW64\dllhost.exe for 64-bit systems. 

If you don’t know which bit your PC runs on, press Windows+R and type “msinfo32” to confirm.

  • Double-click on the dllhost file, and click on Apply.
  • Lastly, hit the OK button to save changes. 

Fix 3: Re-register the DLLs

  • In the Windows search bar, type “cmd” and select Open as administrator for Command Prompt app. 
  • Next, type the following command one by one.

regsvr32 vbscript.dll 

regsvr32 jscript.dll

Fix 4: Check for Disk Errors

This method will help you check for issues in the particular drive you came across the error while opening a folder in it.

  • To get started, press Windows+E and click on This PC from the left panel. 
  • Right-click on the drive you want to check errors for and select Properties
  • Click on the Tools tab and hit the Check now button under the Error-checking option (usually first.)

COM Surrogate High CPU Usage

The Windows COM Surrogate processes are supposed to use little memory and CPU. If you see these processes taking a noticeable CPU usage, they are likely to be a potential threat.  

The only effective solution to this problem is to let your antivirus take care of it. Sometimes these viruses can be tricky to track down for an antivirus, so we suggest you scan your device using different antivirus programs. You must do this, especially if your PC has started malfunctioning or showing adverse effects. 


I hope this extensively curated guide helped you learn about Windows COM Surrogate processes and related errors. We have tried to cover everything we found valuable for the topic. If you still have any questions you haven’t got the answers to, do let us know. 



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