Preinstalled system applications and the Start menu may not work on some computers when you upgrade from Windows 8 to Windows 10 Version 1511.
This issue occurs because of a race condition that causes certain registry keys to become inaccessible to logged-in users. Therefore, the preinstalled system applications that have to touch those registry keys can't be installed during the appx deployment phase.
How to get this update
Method 1: Windows Update
This update will be downloaded and installed automatically.