Security Startup Utility won't accept admin password

livin1965

I am using a 16" MBP on 10.15.2 and trying to change the security settings so I can boot from a backup drive. I am the admin on my computer. Security Startup Utility asks for an administrator password but will not accept the password I use the login to my computer and authenticate application installs, etc. It will not accept being left blank. I have rebooted my computer and done resetpassword from terminal. The admin password continues to function for all the usual activities on the computer, but will work to access Security Startup Utility. Why is this happening and how to fix it?

livin1965

Problem solved by booting into Recovery Mode and performing reinstall of the OS (10.5.2). After the reinstall was completed, I rebooted again into Recovery Mode, launched Security Startup Utility and entered my Administrator password when prompted. This time, it accepted the same password that I use for logging into the computer and the application opened.