Cant deactivate Thread Layout

How can I deactivate the Thread Layout? After an Update one of our Users was confronted with an activated Thread Layout. Somehow I cant deactivate it and even reinstalling or deleting all Data through the Registry doesnt affect the option. Even most Options in the Taskbar that seemed normal for me wont show up, for Example editing the Layout or even resetting it. Someone here with the same Problem or ever heard of that?

If I deactivate the Threadview it vanishes and pops on 2 seconds after.