What Is COM Surrogate Doing on My Windows PC?

Dlllhost.exe explained

If you're worried about COM Surrogate, chances are you've come across it in your task manager and are concerned it might be a virus. Before you go and format your machine or replace any hardware, know it's almost certainly not. And in either case, you don't want to delete it. The COM surrogate process is needed to load DLL files and is actually quite important.

The information and instructions in this article apply to Windows 10, Windows 8, and Windows 7.

What is COM Surrogate?

COM Surrogate is an overarching name for a process called dllhost.exe that has been in Windows since Windows 7 and is present in Windows 8 and Windows 10, too. You can see this yourself if you open task manager, right-click (or tap and hold) COM Surrogate, then select Go To Details. It runs on your username, rather than System or Local Service.

COM Surrogate is a catchall term for a number of processes that perform a number of tasks, and effectively isolate DLLs from the main Windows file explorer. It can be used for quite mundane tasks, like grabbing thumbnails for images or documents in a folder. The reason for that is if anything goes wrong with those DLLs—say they crash, for some reason—they won't take Windows Explorer with them.

It's basically Windows' way of isolating itself from problematic bits of code which could cause stability issues. COM Surrogates effectively make your Windows PC more stable.

Does COM Surrogate Consume System Resources?

COM Surrogate processes do use some system resources, but only a very minor amount. We're talking one to two percent of your CPU if you end up with a great number of COM Surrogate processes running at the same time. It shouldn't be particularly noticeable.

Is COM Surrogate a virus?

The short answer is no. COM Surrogate processes themselves cannot be viruses. However, that's not to say viruses and malware can't disguise themselves as a COM Surrogate process.

How to Check if COM Surrogate is Malware

You can check to see if your COM Surrogate processes are potential malware in the Task manager. Right-click (or tap and hold) COM Surrogate, then select Open File Location.

Com Surrogate

If that leads you to the C:>Windows>System32 folder and a file named dllhose.ext, then you can rest easy knowing COM Surrogate is almost certainly not spoofed malware.

If it takes you somewhere else, however, particularly to a file or folder you don't recognize, it would be a good idea to do an anti-malware scan. Have it target that specific file or folder to be doubly sure.

You might want to consider booting Windows into safe mode first, as active running malware can sometimes hide or copy themselves when faced with quarantine or deletion.