#mpfilt.sys

I’m a very lazy person, my laptop can tell the truth about it. If my PC is clean after a successful spyware/virus scan, the next they something comes back. On my laptop I have two Windows 7 OS. One for work, one for everything else. I had a problem with my USB ports for months with the “freetime” OS (:P) I didn’t know what caused the problem, but every time i started the computer, the USB ports were not functional. I had to check the device manager and disable every usb port, and the re-enable them. Every time. I was too lazy to reinstall the OS and set every single program/driver operational after it. I serached for weeks for the solution. When I installed SUPER AntiSpyware, the program filtered out the suspicious files. Then I found the mpfilt.sys file that caused my problem. I found the solution on a forum (after thousands of searches), so I thought I share it, it could be useful for someone.

Enough from the speech, here’s the solution:

USB corrupted by filters - polished

Navigate to C:\Windows\syswow64\drivers rename mpfilt.sys to mpfilt-USBerror.sys restart your machine

Launch RegEdit Start Menu ==> run ==> regedit Note: You can also launch RegEdit using the Start Menu Search box ==> regedit, then DblClick regedit presented in the search results

In RegEdit Navigate to HKEY_LOCAL_MACHINE\system\currentcontrolset\services\mpfilt

delete the mpfilt key

Navigate to HKEY_LOCAL_MACHINE\system\controlset001\services\mpfilt

delete the mpfilt key 

Note: mpfilt might exist on additional control sets, check each controlset(002,003,010...)\services\mpfilt

delete the mpfilt key

Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{36FC9E60-C465-11CF-8056-444553540000}

delete value "Lowerfilters "

Navigate to HKEY_LOCAL_MACHINE\SYSTEM\controlset001\Control\Class\{36FC9E60-C465-11CF-8056-444553540000}

delete value "Lowerfilters "

Navigate to HKEY_LOCAL_MACHINE\SYSTEM\controlset002\Control\Class\{36FC9E60-C465-11CF-8056-444553540000} .

delete value "Lowerfilters "

Navigate to the top of the RegEdit window "Computer" (in regedit)

Search for mpfilt - it is important to search only for mpfilt - you don't want to find mpflt or mpfilter.

-> RegEdit Search: regedit edit menu -> select find -> enter mpfilt in the search box.

-> Mark Checkbox labeled "Match whole string only"

-> click "Find Next" button until you get the "Finished searching through the registry" message, Click OK

If mpfilt was found when you searched, you probably just missed one. That's why you did the search.

- make sure that it is mpfilt and the key is a service in a controlset, then delete the key