If while carrying out any command on bcedit.exe, you receive the following message:

The boot configuration data store could not be opened

See which of the following helps you:

1] Run CMD as administrator and execute the following command:

bcdedit /set {current} Description "TheNameYouWant"

2] In an elevated CMD execute:

bcdedit /store c:\Boot\BCD

This will give you a list of options.

Execute the following:

bcdedit /store c:\Boot\BCD /set bootmenupolicy legacy

Restart your computer, choose your Windows and imediately press F8.

3] If it does not work you may have to rebuild BCD. You can manually rebuild the Boot Configuration Data store by using the Bootrec.exe tool in the Windows Recovery Environment or you can use this free tool to repair BCD.