dllhost.dll at ~100% CPU usage in Windows XP

Hey there,

I’ve done a lot of Google and Microsoft Knowledge Base searches about this, and everything I’ve found is way too difficult for me to understand… So I’m hoping someone here might be able to help me.

I don’t know if one of the worms has caused this or what, but my computer has been running very slowly lately. I opened up the process manager in Windows XP and saw that dllhost.dll is consistently using 90%+ of the CPU… I’ve tried doing a system restore to earlier dates, virus scans, Microsoft updates, etc, and nothing has helped. Finally, I decided to just click “end process” on dllhost.dll, and that returned everything to normal… But isn’t this an essential process? Why does it come back everytime I turn on my computer? Weird weird weird. From what I’ve found on Google, many other people have had this problem. But like I said, the explanations as to what cause it are over my head…


Dllhost means that your computer is acting either as a host or a server, transferring documents back and forth between your computer and another. This may be a result of file sharing software. It would probably still be this high if you were not connected to the internet, since your computer would constantly be trying to make contact with another computer. It will continually do this every time you restart your computer, until you do something about it.

Either uninstall all of your file sharing software, or…

Try doing this. Start -> Run. Type in, “msconfig,” and hit enter.

A box will open up with different tabs. This shows the environment that your computer boots into. Uncheck anything that you do not want to start up with each reboot of your computer. If in doubt, leave it alone.

Sounds like you might possibly have gotten the Welchia worm.

(PS - I found this information off the 5th site listed when I googled “dllhost.dll”)