Remove Driver Filters to Resolve Device Manager Errors on Windows 7

Thursday, February 16, 2012 posted by CSch

Sometimes the situation might come up where a device that was working flawlessly before will stop doing so, even if you try everything – replugging it, reinstalling its drivers, rebooting the computer – but nothing will help.

A possible cause for this is a driver filter that was either installed by any third party software or simply was corrupted. These can be part of any hardware driver and can intercept requests between software and driver (UpperFilter) or between hardware and driver (LowerFilter). Furthermore, there are two types of filter for each relation – device filters and class filters, where device filters work only for specific devices and class filters work for every device of a specific type, for example every bluetooth radio or every USB device attached to your computer. Those class drivers are the ones that usually cause the issues (if it is a filter issue) because on the software’s side, it makes more sense to address those to alter specific behaviours.

If you experience such an issue (which is commonly recognized by the Device Manager errors 19, 31, 32, 37, 39 and 41) it is possible to delete class filters in the registry. Before you make any changes there, it is highly recommendable to back it up. To do so, enter the registry by entering regedit into a Run… prompt and on the left pane, right-click the topmost key (Computer). Click Export and save the file to any location. The file you just created is a .reg file and can be imported into the registry again by simply double-clicking it.

To find the correct filters in the registry, navigate to the Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class key. This will have many subkeys all named like this: {36FC9E60-C465-11CF-8056-444553540000}. These represent the different classes of hardware, you can sport their type by the (Default) or Class values. The one above is for all USB devices:

Along with the other values, those keys contain the class filters if any are present. They are named UpperFilters and LowerFilters. If you have backed up your registry, look for the device giving you headaches and remove the class filters by right-clicking and deleting them.
This guide is only a solution to a possible source of errors and does not cover the whole range – if the problem persists, the source most likely lies somewhere else.

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One Response to “Remove Driver Filters to Resolve Device Manager Errors on Windows 7”

  1. Serge says:

    Just to be clear this means delete the value UpperFilters and or LowerFilters
    and NOT the entire key {36FC9E60-C465-11CF-8056-444553540000}

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