What do LowerFilters and UpperFilters CD/DVD driver registry settings do?

Solution 1:

See http://djlizard.net/2007/04/30/230/ for a brief explanation of filter drivers. In short:

• Upper filter drivers go between the operating system and the main driver, and lower filter drivers go between the main driver and the hardware.

• Each of the filter drivers should be present in C:\Windows\System32\Drivers with a .sys extension.

• You need and should only remove filter drivers that are causing a problem or do not exist on the system, leaving no blank lines and keeping each driver on its own line. Otherwise, as the Microsoft article says, you will have to reinstall programs such as CD burning software and iTunes.