This is not a case of Program X messing with registry. This is the user explicitly setting Program X to be the default application. I guess there is no way (g

This is not a case of Program X messing with registry. This is the user explicitly setting Program X to be the default application. I guess there is no way (given the current registry design) to differentiate between the user modifying the registry and a program modifying the registry. Again, coming back to the original message - the case scenario is not that some program is changing the preferences. It the user changing the setting, and Win10 silently discarding the user input (after a reboot or some automated update).