Late 2014 Mini won't boot from external disk unless I manually select it in boot manager by holding down option key at startup
I have a late 2014 Mac Mini running Catalina that always boots from the internal hard drive, even though the startup disk system preference correctly shows that the external usb drive is selected to boot from. I have to hold down the Option key at boot to bring up the startup manager which shows the external drive with an arrow below it which I think indicates that is the default boot drive and click on the arrow. The Mini then correctly boots from the external usb drive with no problems. If I reboot or shut down the computer it will boot from the internal drive again. This wouldn't be such a problem but this computer is headless and I don't have easy physical access to it. Any thoughts what else I could do short of disconnecting the internal drive?