Start Menu does not open or not working in Windows 10
Before you proceed, you may want to create a system restore point first, so that you can revert back, if you find that the results are not what you expected.
1] Download and run the Windows 10 Start Menu Troubleshooter from Microsoft.
2] Run the following command in an elevated command prompt, to run the System File Checker.
sfc /scannow
Restart after the scan is over and see if it helped.
3] Repair Windows Image. Open an elevated CMD copy-paste the following and hit Enter
Dism /Online /Cleanup-Image /RestoreHealth
Restart after the scan is over and see if it helped.
4] Make Start full screen and back. Enable Tablet Mode and Start Screen and then go back. See if this toggling has helped.
5] Open an elevated PowerShell window.
Type the following and press Enter:
Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}
To open an elevated PowerShell prompt, type PowerShell in taskbar Search, and in the result ‘Windows Powershell’ which appears, right-click and select Run as administrator.
After the November Update, if you use this method to fix this problem using the Appx PowerShell cmdlet, it caused problems with your Windows Store apps. But if you have installed Windows 10 Anniversary Update, it is working now.
6] Create a new user and see if it helps. To do this, open an elevated command prompt window, type the following and hit Enter:
net user username /add
Here username is your new user name. You will see a The command completed successfully message. Log into your new account and see if has resolved your issue.
ď‚´ If Cortana or Taskbar search is not working, open Task Manager > File menu > Run new task. Type powershell and select the Create this task with administrative privileges check box and click OK. See this post if your Taskbar is not working in Windows 10. ď‚´ Let us know if anything worked for you or if you have any suggestions to make for the benefit of others.