In my Toshiba Laptop, when I try to boot using external boot I get the error message:
BIOS IS NOT UEFI!
The problem solved after I change Boot mode in System Configuration menu in BIOS setting.
Restart the Toshiba laptop and go to the BIOS menu, (press F2 key many times during computer up)
Make Disable the Secure Boot
Go to System Configuration menu
Change the UEFI Boot to CSM Boot to allow the system to boot from external devices