How To Delete the UpperFilters and LowerFilters Registry Values

Removing the UpperFilters and LowerFilters registry values from the Windows Registry is a likely solution to several Device Manager error codes in Windows 7, Windows Vista, and Windows XP.

Prefer screen shots? Try my Step by Step Guide to Deleting the UpperFilters and LowerFilters Registry Values for an easy walk-through!

UpperFilters and LowerFilters values, sometimes incorrectly called "upper and lower filters," might exist for several device classes in the registry but those values in the DVD/CD-ROM Drives class tend to corrupt and cause problems most often.

Note: A few of the more common Device Manager error codes that are often caused by UpperFilters and LowerFilters issues include Code 19, Code 31, Code 32, Code 37, Code 39, and Code 41.

Difficulty: Easy

Time Required: Removing the UpperFilters and LowerFilters values in the Windows Registry takes less than 10 minutes
Here's How:

1. Click on the Start button.

If you're using Windows XP, also click on Run.

2. In the search box (Windows 7 and Windows Vista) or the Run textbox (Windows XP) type regedit and click OK or press the ENTER key.

This will open the Registry Editor program.

Important: Changes to the registry are made in these steps. Take care in making only the changes outlined below. While it's not a necessary step to complete this process, I recommend that you play it safe by backing up the registry keys you're modifying.

3. Locate the HKEY_LOCAL_MACHINE folder under Computer/My Computer and click the |> or (+) icon next to the folder name to expand the folder.
4. Continue to expand folders until you reach the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class registry key.
5. Click on the |> or (+) icon next to the Class key to expand it. You should see a long list of subkeys open up under Class that look something like this: {4D36E965-E325-11CE-BFC1-08002BE10318}.

Note: Each 32-digit subkey is unique and corresponds to a particular type, or class, of hardware in Device Manager.

6. Determine the Correct Class GUID for the Hardware Device. Using this list, find the correct Class GUID corresponding to the type of hardware that you're seeing the Device Manager error code for.

For example, let's say your DVD drive is showing a Code 39 error in Device Manager. According to the list above, the GUID for CD/DVD devices is 4D36E965-E325-11CE-BFC1-08002BE10318. Once you know this GUID, you can continue to Step 7.

7. Click the registry subkey corresponding to the device's Class GUID that you determined in the last step.
8. In the results that appear on the window on the right, locate the UpperFilters and LowerFilters values.

Note: If you only see one or the other value, that's fine. Just complete Step 9 or Step 10 below.

9. Right-click on UpperFilters and choose Delete.

Choose Yes to the "Deleting certain registry values could cause system instability. Are you sure you want to permanently delete this value?" question.

10. Repeat Step 9 with the LowerFilters value.

Note: You might also see an UpperFilters.bak or LowerFilters.bak value but you do not need to delete either of these. Deleting them probably won't hurt anything but neither one is causing the Device Manager error code you're seeing.

11. Close Registry Editor.
12. Restart your computer.
13. Check to see if deleting the UpperFilters and LowerFilters registry values solved your problem.

Tam pen kei man ka test ngiet ahi aa : it work for me
By : Zo Sangpy