Need help in removing an unused drive from the Norton S&R 2 backup destinations

I recently changed from the USB ext HD that I was using for Norton S&R 2 backups and started using 2 USB3 ext HDs. I backup my computer to one HD then I backup my computer to the other HD.  I moved the recovery points that I felt I needed to the new HDs and deleted them from the old HD. I also set one of the new HDs as the default backup destination. But when I open Norton S&R the Home page says I’m at risk because no Recovery Points exist on the old HD. When I go to the Advanced Page it shows that old HD as “at risk”. If I right click on the drive the “remove drive from the list” choice is not there. I plan on using this HD for other things, but I do not want it listed as a backup destination. I would really appreciate any help/advice on solving this problem. Thank you.