Windows 7 wont boot without AHCI

**Mighty Clark** · 04-09-2009

I recently went to my cousins house & she wanted to install windows 7 & i have helped her in installing Windows 7... It was firstly gave me an error on AHCI for windows 7 to install & then when i enabled it, It worked fine .... So i wanted to know??? What is AHCI???? & why Windows 7 won't boot without AHCI????

**Eric B** · 04-09-2009

Advanced Host Controller Interface
The Advanced Host Controller Interface (AHCI) is a programming-specification which defines the operation of Serial ATA host-controllers (also known as host bus adapters) in a non implementation-specific manner. The specification describes a system memory structure for computer hardware vendors to exchange data between host system memory and attached storage-devices. As of June 2008, the current version of the specification is v. 1.3.[1] AHCI offers software developers and hardware designers a standard method for detecting, configuring, and programming SATA/AHCI adapters. AHCI is separate from the SATA 3Gb/s standard, although it exposes SATA's advanced capabilities (such as hot-plugging and native command queuing) such that host-systems can utilize them.Eric B

**ThoMas321** · 04-09-2009

To do this, follow these steps :

Exit all the Runing.
Now Open Registry Editor.

Locate the following registry subkey:

Code:

HKEY_LOCAL_MACHINESystemCurrentControlSetServicesMsahci

Now right Click on it & Click on Modify.
Change the Value to 0 & click OK.
On the File menu, click Exit to close Registry Editor.

**MrChris-** · 04-09-2009

If they have not initiated AHCI in the BIOS when the operating system settles, then the operating system does not install the controllers. If soon it entered the BIOS and ahci it initiated after installs Vista. The unique way to solve it is to return to install the initiated operating system with AHCI in the BIOS, because if you try to make a repair and have allowed AHCI after you made the installation in way IDE will erase the hard disk and you would have to return to install the operating system anyway. Its same way with the controllers RAID that you want that his disc of starting RAID.