Quote Originally Posted by oldfred View Post
Not sure if you have UEFI boot menu or Windows boot menu when it has more than one Windows.
But grub cannot modify either of those.
Typically grub will just have the one entry to chainload the Windows .efi boot file in the ESP.
Windows only has one set of boot files with two entries in its BCD which is not parsed from Linux.
I would guess it is a windows 10 boot menu. Possibly a windows 8-or-10 boot menu.
If I were to use that grub menu line, then I first get an error screen telling me there's a problem with the operating system I linked to - also I believe a product of windows 10 simply trying to have total control over the system.

As long as I DON'T use that grub menu line, all is well.

As to who does what, I can only guess.

many thanks for your time!!!!!!!!!