When I start my Win10, I am asked to make a choice between two 'identical' Win10 systems, one being 'qualified' as (Volume 1). If I chose the other, booting into Win10 does NOT happen. How can I eliminate this false choice ?
Probably, the easiest would be to use something like EasyBCD https://neosmart.net/EasyBCD/#comparison
Free for non-commercial use.
You still need to be careful when editing the Boot Configuration Data and I would advise a full system image before proceeding.
I've had a look at that site, and it is not immediately obvious that it will address my need. But your post has made me remember that I edited the boot.ini (?) file in WinXP to achieve a similar effect - set a default O/S (thus removing the prompt for a choice). I have to make the ini file visible first (if it exists in Win10), and then edit it in Notepad. Can you refresh me on the details as they would apply in Win10 ?
XP was the last of the boot.ini file editing.
Everything from Vista on (I believe) is done by editing the BCD (Boot Configuration Data) file. Which is what EasyBCD does.
There are other means of doing it, but as I stated above it is probably the easiest and most user friendly method of doing so.
EDIT: There is plenty of documentation, I believe you should start here with Easy BCD basics and maybe look at the section on deleting entries. Again...... protect yourself from unintended consequences by making a system images first. https://neosmart.net/wiki/easybcd/basics/