Like its previous versions, Windows 10 also supports pinning certain objects to the taskbar for instant access like certain files, folders, or any other kind of shortcut. To do so, you just need to click on the file and select pin to start option. But sometimes the option Pin to startup does not appear in the context menu of supported files. If the option Pin to start does not appear when you right-click on a folder, .exe file, or shortcut, a policy called Prevent users from customizing their Start Screen or another policy called LockedStartLayout has been enabled.
Restore the missing “Dock to startup” option using Registry Edit.
Manually edit the registry to correct this error step by step.
Type regedit in the start menu or in the search box on the taskbar and press Enter. This will open the registry editing windows. Now navigate to
HKEY_CURRENT_USER SOFTWARE Microsoft WindowsCurrentVersion Policies Explorer
On the right hand side, look for the entry that says NoChangeStartMenu and delete it.