Upper and Lower Filters Location in Registry

This guide outlines the precise locations in the Windows Registry Editor (Regedit) where UpperFilters and LowerFilters are defined for optical (CD/DVD) and disk drives. Upper and Lower filters are driver-level components that modify or intercept I/O requests to hardware classes. When third-party burning software, backup tools, or virtualization utilities leave behind corrupted filter entries, Windows often fails to recognize connected drives and displays Device Manager errors such as Code 19, Code 31, Code 32, Code 39, or Code 41.

Optical Drives (CD/DVD-ROM) Filter Location

For optical disc drives (CD, DVD, and Blu-ray), the UpperFilters and LowerFilters values are stored within the following registry key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E965-E325-11CE-BFC1-08002BE10318}

Inside this key, look at the right-hand pane for the multi-string values named UpperFilters and LowerFilters.

Disk Drives (Hard Drives and SSDs) Filter Location

For internal hard drives, solid-state drives, and standard fixed disks, filter drivers are defined under a distinct class GUID:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E967-E325-11CE-BFC1-08002BE10318}

Any drive-level filter drivers affecting mass storage disks will appear in the right-hand pane under UpperFilters or LowerFilters.

How to Access and Modify Filter Values

  1. Press Windows Key + R, type regedit, and press Enter to open the Registry Editor.
  2. Paste the desired registry path into the address bar at the top of the window and press Enter.
  3. In the right pane, locate the UpperFilters and LowerFilters values.
  4. To resolve drive recognition errors, right-click the offending filter entry, select Delete, and confirm the action.
  5. Restart the computer for the changes to take effect and allow Windows to reload the standard device drivers.