Why: Running bless to place boot files failed. – RAID Mac OS High Sierra 10.13
After installing or restoring from a Time Machine backup with Mac OS High Sierra 10.13 to a RAID hard drive, the installation or restore may appear to complete and show a startup disk, but when you attempt to boot from it you receive a message running bless to place boot files failed. This is because the latest version of Mac OS High Sierra does not officially support RAID drive configurations.
However, you can force install Mac OS High Sierra 10.13 onto a RAID slice using the SuperDuper method. Follow our article in this link.