Oct 22 23:43:36 ubuntu-mate grub-installer: Installing for x86_64-efi platform. Oct 22 23:43:36 ubuntu-mate grub-installer: grub-install: warning: Internal error. Oct 22 23:43:36 ubuntu-mate grub-installer: grub-install: error: failed to register the EFI boot entry: Operation not permitted. Oct 22 23:43:36 ubuntu-mate grub-installer: error: Running 'grub-install --force --target x86_64-efi "/dev/sda"' failed.
Oct 22 23:43:36 ubuntu-mate grub-installer: Installing for x86_64-efi platform.
Oct 22 23:43:36 ubuntu-mate grub-installer: grub-install: warning: Internal error.
Oct 22 23:43:36 ubuntu-mate grub-installer: grub-install: error: failed to register the EFI boot entry: Operation not permitted.
Oct 22 23:43:36 ubuntu-mate grub-installer: error: Running 'grub-install --force --target x86_64-efi "/dev/sda"' failed.