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How to Fix COM Surrogate Process Issues: What Is COM Surrogate?

If you visit the Processes tab in the Task Manager on Windows 10, you will likely see a process called ‘COM Surrogate’. The process does not give away what it does and you may see more than one instance of it running. 

COM Surrogate is not a virus. It is a Windows 10 process that provides support and safety to apps that do not want to host a COM object under their own process thread.

COM Surrogate

What Is COM Surrogate?

Basically, Windows 10 apps can run COM objects. These objects allow an app to extend its capabilities Think of it in terms of an add-on for a browser i.e. an add-on extends what a browser can do but an add-on runs as a process under the browser. COM objects may or may not be safe, and they may or may not be stable. 

If a COM object is unstable, it can crash the app that started it. To avoid this, Windows 10 has the COM Surrogate service. It creates the COM object outside an app’s process and allows the object and the app to connect. If the COM object created by COM Surrogate crashes, the crash does not affect the app that was using it. 

The name ‘Surrogate’ hints towards its function; instead of the process being ‘carried’ by the app that needs it, it is carried by an independent process that runs outside the app. The process itself has no function. It does or runs what other apps need it to run so the process may be responsible for generating thumbnails for certain file types or it may be responsible for running an API for Cortana.

Fix problems with COM Surrogate on Windows 10

COM Surrogate is used by quite a few apps, many of them stock Windows 10 apps. Problems with COM Surrogate will prevent certain features in an app from running. The app will run but you will get an error message telling you that COM Surrogate isn’t running. Here are a few things you can try to fix the problem.

1. Close/restart COM Surrogate

COM Surrogate is a process like any other process and as such, it can run into problems. As with many apps and processes, restarting the COM Surrogate process can fix problems with it.

  1. Right-click the taskbar and select Task Manager from the context menu.
  2. Go to the Processes tab.
  3. Look for COM Surrogate and select it.
  4. Click the End Task button at the bottom right.
  5. Repeat for all COM Surrogate processes.
  6. Access the file or run the app that originally showed a COM Surrogate error. 

COM Surrogate Process

2. Install media codec

Problems with COM Surrogate can be caused by media codecs. Specifically, if you have a file that requires a special codec to be installed in order for it to generate thumbnails, make sure that you’ve installed them. If there’s a problem with the codec, uninstall and reinstall it.

3. Find and delete problem file

COM Surrogate may be having a problem trying to generate a thumbnail for a particular file. To fix this, you have to delete the file in question. 

  1. Open File Explorer and go to the View tab.
  2. Click the Options button and select ‘Change folder and search options’.
  3. Go to the View tab and enable the ‘Always show icons, never thumbnails’ option.
  4. Click OK and Apply.

  1. Open File Explorer and navigate to This PC.
  2. Right-click the C drive (or your Windows drive) and select Properties from the context menu.
  3. Go to the General tab and click Disk cleanup.
  4. In the window that opens, select Thumbnails and click OK.
  5. Allow Disk cleanup to run.

  1. Download the Process Monitor tool. 
  2. Look for the dllhost.exe process and which file it is trying to access.
  3. Delete the file.
  4. Restart COM Surrogate (see previous section).
  5. Enable thumbnails again (Steps 1-3).

4. Check antivirus

Many users use third-party antivirus apps. There’s nothing wrong with using a third-party app but a particularly zealous one may block essential Windows 10 services like COM Surrogate.

  • Whitelist the COM Surrogate process in your antivirus app.
  • Disable your antivirus and use Windows Defender which will not block COM Surrogate.
  • Update your antivirus and its virus definitions.

Conclusion on the COM Surrogate Process

COM Surrogate isn’t a virus and you should not try to remove or block the process on your system. If it’s consuming a lot of CPU, check which file it is trying to access or which app is using it and troubleshoot it.

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