Update 1/24: New user did not permanently fix the problem. For a temporary solution, restart the "Runtime Broker" process in Task Manager.
Update 12/7: Windows Event Viewer reports the following: Shell Experience host application hang and error paired with a cortanaUI error for everything taskbar click.
Since updating to Windows 10 Release 10586, I am periodically having the following problem with the Start Menu and Windows Store Apps (including the Windows Store itself and Edge, but not Windows Feedback). I did attempt to contact support through the support application before it failed, but it eventually froze during the conversation. At this point I rolled back to the previous release (10240).
Problem: Windows Start Menu Fails to open, Windows Store Apps fail to open
1) Install Windows 10 Release 10586 (1511.14) including all Windows Updates
2) Wait indeterminate period of time - having trouble finding the exact trigger.
3) Open Windows Store Apps as below (this includes all downloaded applications from the store running the Universal Framework).
Apps freeze on UI load screen - i.e. the solid color screen w/logo
4) Windows Start Menu stops responding, as well as system tray icons (including Action Center)
PC: Sony SVS151190X.
CPU: Intel Core i7 3610HQ
GPU: Switchable IntelHD 4000 / Nvidia 640M LE 2GB (Kepler)
1) Restart fixes the problem for a short indeterminate period, and then freezes again.
2) Attempting a Windows Explorer restart in Task Manager has no effect.
3) SFC /scannow reports a corrupted "opencl.dll" file which cannot be repaired. DISM reports image not available to repair.
4) Clean boot attempted, prolonged the time to failure (~1 hour) but ultimately failed again
5) Rolling back to previous build solves the problem, rolling forward again breaks it again.
In the case of Edge, the browser opens but loads an empty webpage (not Cortana start or "where to next", actually blank) and does not respond to input.
Edge refuses to close normally and must be forced closed from Task Manager. This differs from other apps which do close normally.