Occasionally, the Start button, Taskbar, and the Notification area icons may get stuck or frozen; clicking them does nothing. When the items in the Notification area are frozen, you wouldn’t be able to access Action Center, Wi-fi network settings, etc.
If the Windows 10 Start Menu is frozen or non-responsive and does not work, or shows the Critical Error message, here is the list of troubleshooting steps you can follow. The fixes involve running the Start menu Troubleshooter or manually registering the ShellExperienceHost & StartMenuExperienceHost packages using PowerShell or restoring the default Start menu by rebuilding the Start menu database.
This article explains how to repair, reset, or reinstall the Start menu in Windows 10.Read more