AHCI (Advanced Host Controller Interface is a Windows component that allows for NCQ (Native Command Queuing) and hot-plugging or hot-swapping through SATA Serial-ATA host controllers possible. AHCI was first introduced in Windows Vista. The problem with AHCI is that it needs to be enabled in the BIOS of a computer before the Windows OS is installed since Windows deletes AHCI drivers during OS installation. Attempting to enable AHCI in a computer’s BIOS after OS installation results in the computer becoming disabled.
Fortunately, it is possible for AHCI to be enabled on a computer running on Windows Vista or Windows 7 after BIOS installation, and if you wish to do so, the steps you need to perform are listed below.
Press Windows Logo key + R to open a Run
Type regedit into the Run dialog and press Enter. If prompted by UAC, confirm the action.
In the left pane of the Registry Editor, navigate to the following directory:
Click on msahci in the left pane of the Registry Editor to expand it in the right pane.
Double-click on Start in the right pane to modify it.
When the Edit window opens, change whatever value is in the Value data field to 3.
Click on OK.
Check to see if there is a folder named iaStorV in the left pane. If there is such a folder, click on it to expand its contents in the right pane. Once it has been expanded, double-click on Start in the right pane to modify it, change whatever value is in the Value data field to 3 and then click on OK.
Close the Registry Editor.
Restart your computer, and while it is booting up, access its BIOS and enable AHCI in its BIOS.
When the computer boots up, Windows will start installing AHCI drivers. Let it do so. Once Windows is done installing AHCI drivers, AHCI will have been enabled on your computer successfully.