It says 'solved' but is "format c:" really a solution or rather a bandaid? Just like realpinkman I'd prefer not having to reinstall windows.
And like realpinkman I don't have a winstore on my c...

So I've narrowed the behaviour down a little. I use two monitors with taskbar enabled on both. Once I've used the windows start button on a particular monitor the taskbar on that will no longer...