This appears to be the same as bug #1694986.
Do you remember being prompted previously about turning off SecureBoot? Did you elect not to turn off SecureBoot? Or, did you choose the option to disable SecureBoot, but not confirm this selection on reboot?
This appears to be the same as bug #1694986.
Do you remember being prompted previously about turning off SecureBoot? Did you elect not to turn off SecureBoot? Or, did you choose the option to disable SecureBoot, but not confirm this selection on reboot?