I have had the same problems since the last Windows 10 update done around 18 April. I have been researching and trying possible solutions for a week now most days as time allows and/or until I get worn out. My specifics: Login screen displays then after login, I get the black screen with movable cursor. I am able to get to Task Manager and can stop AppReadiness, but it doesn't bring up the desktop or stay stopped if I restart and go to Task Manager again. I have an HP Envy notebook upgraded from Windows 8 Pro to Windows 10, Intel CORE i7 processor. I have also been using the HP forum, but it doesn't sound like this is strictly an HP issue.
From Task Manager, I was also able to do File > Create New Task and click Browse. As someone said, it's like Windows is running back there but can't get to it. That brought up an Explorer view window, but it was not very responsive. I was able though to execute winver in the box and get my version/build info.
I will continue to research and try options, but getting very weary. I just wanted to at least for now add my system to the list that this update seems to have messed up. Help please.