Microsoft has integrated the driver userChoice Protection Driver, short UCPD, into Windows 10 and Windows 11 systems recently. This driver has just one purpose: to block access to UserChoice Registry keys.
These Registry keys define the default programs on the system. There are keys for the default web browser, PDF Viewer, or image editor. Keys exist for file extensions and protocols as well.
Microsoft introduced a new convoluted way of
changing default apps and file extension associations in Windows 11 for users. You can check out our guide on
setting default apps on Windows 11 here.
Up until recently, programs could make changes to the UserChoice Registry keys to change default parameters. A web browser could set itself as the default program for all supported file types. Provided that the user wanted this, it make things a lot easier thanks to the automated way of changing defaults.