1

Background

Advanced Host Controller Interface (AHCI) is a technical standard defined by Intel that specifies the operation of Serial ATA (SATA) disk controllers. When it is supported by your operating system and PC hardware, you will get the benefits of features such as native command queuing and hot swapping. For an older OS like Windows XP which does not support AHCI mode out of the box, without OEM-supplied drivers, it is possible to turn on the legacy (IDE) mode in the BIOS to get it to install properly. If your installed your Windows 7 or Windows 8 accidentally in the legacy IDE mode, and want to switch to the AHCI mode, Windows will not boot after you switch from IDE to AHCI in the BIOS.

Goal

This question aims on solving this problem with Windows Vista 32-bit installed on a SATA drive in BIOS IDE mode, as to how exactly to proceed when one wants to switch to AHCI without OS re-installation.

Vlastimil Burián
  • 4,376

1 Answers1

2

  1. Open regedit, the Registry Editor.

  2. Navigate to the following DWORD value:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci

  3. Change the Start value from 3 to 0.

  4. Reboot your PC and immediately set the SATA mode to AHCI.

  5. Windows Vista will now boot successfully, though it might take considerably longer time than you are used to. Or at least, in my case it caused this.

  6. Once Windows finally boots up, it will auto-detect the change and install AHCI driver itself.

  7. In the end, you will be prompted to reboot to reflect the changes, just do it.

  8. You might want to use any kind of driver updating software to fully update the AHCI driver. Among with other drivers when you are at it.

Vlastimil Burián
  • 4,376