Enable AHCI Without Reinstalling OS in Windows 10 and 7

AHCI (Advanced Host Controller Interface) mode is a communication mode that serves to connect storage devices using SATA interface with the support of NCQ and hot plug features. On practice AHCI mode often provides faster read/write speeds while using HDDs and especially SSDs. Quite often users find that they have AHCI disabled and try to enable the mode in UEFI (BIOS) but get the BlueScreen issue with the code Inaccessible_boot_device. In this article we will explain how to check if AHCI is enabled and how to safely enable AHCI mode without reinstalling Windows 10 or 7 and avoid BSOD.

Why You Need AHCI Enabled For SSD

Don’t think that AHCI is useless for you. I know why you think it is – because someday you tried to enable AHCI mode when you were using a classic HDD (Hard Disk Drive) and AHCI did not boost the speed. But it works for SSD! Even if you have an old SATA 2 controller you will feel the difference in read and write speeds when you enable AHCI mode. Look at the SSD performance comparison on my old HP G62 from 2011:

AHCI mode on SATA2

SSD speed with AHCI vs IDE on SATA2 controller

How To Check Whether AHCI Is Enabled Or Disabled

  1. Open the Device Manager.
  2. Expand the IDE ATA / ATAPI Controllers.

If you see AHCI Controller in the list, you have it enabled:

SATA Controller AHCI Mode

If you see only ATA and IDE words you are likely to have AHCI disabled on your machine!

Enable AHCI In Windows 10

Launch the registry editor (Win+R, type regedit, press Enter) and perform the following actions:

  1. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\iaStorV and set the value named Start to 0iaStorV start 0
  2. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\iaStorAV\StartOverride and set 0 to 0iaStorV StartOverride 0 0
  3. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\storahci\ and  set Start to 0storahci Start 0
  4. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\storahci\StartOverride\ and set 0 to 0storahci StartOverride 0 0
  5. Reboot your system.
  6. Go to UEFI/BIOS and enable AHCI mode.
    Here is how it looks on an old desktop with AWARD BIOS. You need to go to Integrated PeripheralsAward BIOS Integrated Peripheralsfind SATA AHCI Mode and switch it to AHCISATA AHCI Mode EnableSave UEFI (BIOS) settings and reboot your PC.

Enable AHCI Mode In Windows 7

  1. Launch the registry editor: regedit-win7
  2. Navigate to:
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci
  3. Set the Start value to 0Windows 7 msahci Start 0
  4. Reboot your system.
  5. Go to UEFI/BIOS during the reboot and change IDE to AHCI.

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