BCDEdit is a command-line tool designed to manage the store. The BCD store replaces the old boot.ini file from Windows XP/7. It contains the menu entries, boot parameters, and critical settings that tell Windows 10 how to start.
BCDEdit returns a GUID (e.g., d4ceeeb8-0a2c-11ee-b8a5-ef33d4a4c8ef ). Copy it. Then: bcdedit windows 10