When you setup system on a fresh disk you may encounter a problem of corrupted GPT backup. This will happen even more likely when you messed with MBR before on that disk. Free and Open GDISK utility will help you. GDISK will tell you current state of the disk and partition tables, also warn you on possible problems. When you print available partitions (‘p’) and they seem okay, you can simply write out (‘w’) the partition table, that would fix the GPT backup corruption problem 🙂