Firstly, I am aware of this question possibly being duplicate of Windows 10 Start Button Repeatedly Becomes Non-Responsive
and
Windows 10 Start Menu Stops Working.
The second links says
Try running CMD as Admin, typing powershell, and entering this command: Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}
Taken from: http://forums.windowscentral.com/ask-question/370916-start-menu-not-working-windows-10-build-10240-a.html
However, I am not sure about the 'DevelopmentMode'. This is not a pre-release version. I recently upgraded from Windows 8.1 to 10 and initially start menu and taskbar right-click were working fine. Couple of days ago the problem surfaced. Is there any new solution to this problem?
Till now, I performed update and SFC /scannow
but no luck.
-DisableDevelopmentMode
to function though. SFC isn't going to solve this problem, never has, which is the reason it did nothing.