I've been having this problem for a while on both Win7 and Win10 machines: When I browse to a folder with a certain kind of file in it -- Specifically, large Quicktime files ~100GB -- Windows seizes for a couple minutes. Everything just stutters and locks up.
If I open up Task Manager or Resource Monitor beforehand I can see that it's a COM Surrogate / dllhost.exe instance that appears to be "chewing through" the huge video file, and the system doesn't become responsive again until it finishes.
After tons of Googling and research, uninstalling software, etc. I still can't figure out what's behind it. I'm assuming it's some software I've installed that attached itself to the shell, but the only way I can figure out what it is is to replicate it (which is very easy) and track what piece of software is creating and using the dllhost instance. How can I do that?