I am running several workstations with the following: Prime B250M-A mb, i5-6600 cpu, Samsung 860 ssd, 32gb ddr4 ram. On only one of these workstations, the computer will not boot up each morning. In BIOS, I find that the cdrom has been moved into the top boot position, and the ssd into the last. I drag the ssd back to the top of the list and the computer boots fine. Then the next day the problem repeats itself. All of these mb's have the same revision of 3013 (as noted by AI Suite 3).