The same Edge engine is responsible the start button in Windows 10.  If both stop working or you have problems starting the Edge browser, check the permissions for this registry key:

HKCU\SOFTWARE\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\AppContainer\Storage\microsoft.microsoftedge_8wekyb3d8bbwe

If the permissions for the third “Account Unknown” entry S-1-15-3-3624051433… are Read Only, add Full Control.

This will fix the problem immediately without a reboot.