I had this unusual (or what I thought at the time was unusual) error when using on board Intel RAID for 4 SATA disks. I wanted a RAID10 config for a server build but when I configured RAID10, had all 4 disks in great shape, booted to Windows Server (doesn’t matter which version I don’t think – 2008 +) it gave me the oddest error!
“This computer’s hardware may not support booting to this disk, ensure that the disk’s controller is enabled in computer’s Bios menu”
Looking at the Intel BIOS I noticed it said “bootable no” thus, I now understood why the OS was complaining. It turns out I misconfigured my RAID setup from the start.
What you need to do is configure an OS volume and a data volume. I wanted my OS volume to be something sane anyway so I created a volume of 120 GB and the rest of the 3.x TB as another RAID volume. As soon as I created a boot volume that made sense (the 120 GB) the Intel RAID software flagged it with a “bootable yes”. SUCCESS!
You can now install Windows Server 2008 + on the RAID volume.
Comment if this happened to you and this was the fix ;-)