Hot Plug Issue with Intel ICH9R Controller: Enabling AHCI After Installing Windows (Long) RRS feed

  • Question

  • I recently put together a system using a Supermicro C2SBC-Q motherboard (see below)




    (This motherboard does not have a floppy controller and, therefore, a floppy drive was not installed.)


    and an Intel Core 2 Quad Q9550 (2.83GHz/1333FSB/12MB Cache) processor


    inside of a Supermicro SC733TQ-465B case (see below)




    Both of the following controllers are in the system:


    Intel ICH9 Family 2 port Serial ATA Storage Controller 2 – 2926


    Intel ICHR/DO/DH 4 port Serial ATA Storage Controller 1 – 2920


    The OS is Windows XP (32 bit). The most recent version of the Intel Matrix Storage Manager is installed. In the BIOS, AHCI is enabled while RIAD is disabled.


    The issue is that I can hot plug the drives that were present upon booting the system (for example, the drive in bay 1 can be switched to bay 3 and will be recognized), I cannot take a drive that was not present upon booting and plug it into a bay such that it is recognized by the system. I found the fix below on the web and tried it, but the issue remains.




    This solution was provided by Brian Neckel who is an extremely competent Senior Technical Support Engineer with ASUS. It is reproduced below with his permission.

    Be very careful to follow these instructions to the letter.


    HOWTO: enable AHCI mode after installing Windows


    I managed to successfully enable AHCI mode after installing Windows. Here's how...

    AHCI (Advanced Host Controller Interface) is present on newer Intel chipsets such as 975X (ICH7), P965 (ICH8), and P35 (ICH9). AHCI mode is enabled in the BIOS and 3 settings are commonly available: IDE, AHCI, and RAID. The last two (AHCI and RAID) require a driver floppy and the F6 method when installing Windows XP otherwise the hard disks won't be detected.

    The problem is that if you installed Windows in IDE mode (ie you didn't use F6 and supply a driver disk), then simply changing the BIOS setting to AHCI mode and rebooting will cause Windows to fail and will require a repair install. Most people have been advising to reinstall Windows if you want AHCI enabled.

    I managed to enable AHCI on Windows XP Professional for a Gigabyte P35-DS4 (ICH9R) without needing to reinstall. This should work on any P35 ICH9 based board:

    1. Go to Intel's download centre and download the latest version of the Intel Matrix Storage Manager (, 8/2/2007 at time of writing) for your OS:


    Keep this file as you'll need it again in step 4.

    2. Run the installer with the -a switch to extract the files. This will NOT install the software, just extract the files. Follow the prompts as if you were installing the software:


    iata76_enu.exe -a
    The above should extract the files to \Program Files\Intel\Intel Matrix Storage Manager. There are two folders, \Drivers and \Drivers64 for 32-bit and 64-bit OS's, respectively.

    Copy the file IaStor.sys from the Drivers folder to C:\Windows\System32\drivers\

    3. copy the following registry file to your desktop (copy and paste into notepad) and save as ahci.reg


    Windows Registry Editor Version 5.00


    "Group"="SCSI miniport"
    "DisplayName"="Intel AHCI Controller"



    4. Double check you've copied the IaStor.sys file as part of step 2. Now do the following:

    Run the ahci.reg file to add the entries into the registry
    Reboot the computer and enter the BIOS - DO NOT allow it to start Windows yet.
    Change the setting for the on board Intel controller to AHCI, save and exit BIOS
    Boot into Windows

    When Windows loads it will detect a new hard disk - cancel the wizard for installing the new hardware and run the Intel driver installer you downloaded in step 1.

    Reboot the system again and you're good to go



    Unfortunately, even after all of this my system is not “good to go.” Do any of you have ideas about how I should proceed?



    Monday, March 23, 2009 2:56 PM


  • Hi,


    Thank you for posting.


    I know you want to enable ACHI mode on the Windows XP computer. If I have misunderstood your concern, please feel free to let me know.


    At this time, I would like to share the following documents with you. Hope they are helpful.


    How to do unattended install of AHCI/RAID driver on Windows 2000/XP/Server 2003


    Intel® Matrix Storage Manager


    Please Note: Since the website is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.


    Regarding the issue which occurred on Windows XP and the it is hardware related as well, it is better to go to our Windows XP forum and contact your computer(motherboard)’s manufacture for technical support.


    Hope the issue can be resolved soon. Thanks.

    Nicholas Li - MSFT
    Wednesday, March 25, 2009 10:11 AM