Wednesday, June 10, 2009

AHCI prevents startup on XPS system

A client brought me a beautiful XPS system. The hardware is neatly packed into a small case and is easy to remove. Unfortunately the system failed to start up. I checked the BIOS and it was detecting the hard drive. Other settings seemed normal, however the Advanced Host Controller Interface was active.

AHCI enables hot-plugging of SATA devices, and is normally enabled in a RAID array. As there was only one hard drive present, SATA cabled, I wondered if AHCI was necessary. The alternative was plain-vanilla SATA. After disabling AHCI the computer started up properly. Obviously the AHCI/RAID drivers were not installed or had been corrupted, so the computer halted when booting the drive at startup.

Instead of replacing the AHCI drivers (available from Intel), I turned off AHCI. Activating AHCI really isn't worth the effort on a system with a single drive. You already have lightning-fast access with SATA!