Switch from IDE to AHCI after installing Windows 7 or Windows 8

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. Here is how to fix it.

First switch SATA to the legacy/IDE mode. Please refer to your motherboard manual to learn the exact location of the SATA options in your BIOS.

In Windows 7

  1. Open the Registry editor.
  2. Navigate to the following key
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci

    Tip: How to jump to the desired registry key with one click.

  3. Change the Start DWORD value from 3 to 0 as shown in the picture below.
  4. Reboot your PC and set the SATA mode to AHCI.

You are done. Now Windows 7 will boot successfully.

In Windows 8 and Windows 8.1

Option one

  1. Power down or restart the computer and enter the system BIOS.
  2. Change the ATA Drive setting back to ATA Mode, press enter to accept the change and restart the computer.
  3. Click Yes to the Warning about the detected mode change on the embedded ATA controller.
  4. The system will boot normally to the Start screen.
    NOTE: Be sure you know the Local Admin account and password and are able to boot successfully before proceeding.
  5. Open an elevated command prompt and run the following command to enable Safe Mode boot:
    bcdedit /set {current} safeboot minimal
  6. Restart the computer and boot to the system BIOS.
  7. Change the ATA Drive setting from ATA/IDE Mode to AHCI Mode, press enter to accept the change.
  8. Click Yes to the Warning about the detected mode change on the embedded ATA controller.
  9. The system will boot normally to the Start screen in Safe Mode.
  10. Open an elevated command prompt and run the following command to remove the Safe Mode boot option:
    bcdedit /deletevalue {current} safeboot
  11. Restart the computer and boot normally, the system will boot successfully to the Start screen.

Option two

  • Open the Registry editor.
  • Navigate to the following key
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\storahci
  • Change the Start DWORD value from 3 to 0.
  • Reboot your PC and set the SATA mode to AHCI.

That's it

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25 thoughts on “Switch from IDE to AHCI after installing Windows 7 or Windows 8

        1. Jimmy

          RAID and AHCI driver is virtually interchangeable. You should be able to change your BIOS from RAID to AHCI without changing anything in windows.

          Reply
    1. Ed Tittel

      Thanks, Sergey! I appreciate you taking the time to work through the Windows 8 side of things.
      Best wishes,
      –Ed–

      Reply
  1. Jon

    Please note that AHCI device driver has to be already installed before applying fix
    otherwise this will not work.

    Reply
  2. alturo

    DUDE IVE BEEN TRYING TO CHANGE THIS LEGACY TO AHCI FOR WEEKS. I KEEP GETTING THE SAME ERROR MSN. WHEN I CHANGE THE PC TO AHCI THE WINDOW ICON SHOWS UP UT THEN RESTART IT SELF. ANY ASSISTANCE PLEASE

    Reply
  3. isidroco

    After two days of internet digging and countless failed experiments of all suggested methods, found a simple solutions by myself. Make sure you know how to enter Bios Setup before entering windows (ie: by disabling secure boot, etc).

    1) Boot normally (in IDE mode), go to Device Manager, uninstall all IDE/ATAPI controllers, starting from bottom to top, don’t restart when offered.
    2) Reboot and go to BIOS setup: Change to AHCI mode.
    3) Windows will boot and install or request new drivers automatically.

    For upgrading motherboard:
    2) Change to new motherboard.

    Reply
  4. Mirko Veselinović

    I do have similar problem, but another way! Disk contain installed Windows 7, but “replacement” laptop has no AHCI mode in BIOS (Dell XPS M1710)! What should be done?

    Reply

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