I had the same problem as all of you did so what i did was went into the installed updates, Then i uninstalled the optional updates the one that seem to of fixed it for me was taking of KB3055343. I did what everyone else did checked the forms for a answer but like usual nothing, So i went thru stuff that was installed an found that one being uninstalled seem to do the trick..
Hope it helps others. :)
Glad it worked for you; didn't fix it for me. I uninstalled all updates that were installed after the update icon disappeared from my system tray, rebooted, and still a problem. And the troubleshooter is still telling me KB2976978 is missing and that's
the problem, but it's not missing, and I've reinstalled it multiple times. My computer is less than 2 weeks old, so I know it's not a problem with my computer.