UPMCalc

UserPreferencesMask is a cryptic registry entry that stores many of the Windows visual effects settings and also some input and accessibility preferences. It's a bitmask stored as little-endian hex inside a REG_BINARY value. It cannot be directly edited without the use of bitwise math and understanding of functions of individual bits (which are only partially documented).

That's why UPMCalc was created, it makes it easy to decode and manipulate UserPreferencesMask data. It can be used as a tweaker but if you're looking for a full-fledged Windows visual tweaker, look elsewhere - UPMCalc has a narrow scope since it only deals with settings stored inside UPM.

It is also meant to serve as a detailed and up-to-date UPM reference because presently the only official documentation dates back from Windows 2000 and is not very descriptive. Give UPMCalc a try to fully assess its capabilities!