How to enable AHCI mode for windows 7 and Vista without format.

You just bought a new ssd hardisk and you find out that in order to maximize its performance, use trim and etc you have to use it on AHCI mode. By just changing the relevant option in BIOS windows7 and vista does not boot and return a stop 0x0000007B error.

This error occurred because the AHCI sata driver must be enabled before you change the SATA/RAID mode of the boot drive in bios.

Therefore, go back to bios change the sata mode to legacy, compatible, ide or whatever it was and boot back to windows. The solution is very easy but involves some registry editing.

1. Click Start and type regedit in the Start Search box

2. On the User Account Control warning box, click on YES.

3. Locate following registry subkeys:

  • HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV (In case you have the intel drivers)
  • HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci

achi registry key

4. In the right pane, right-click on Start (Name column) and then click Modify.

5. In the Value box, insert 0, and then click OK.

6. On the File menu, click Exit.

7. Reboot, and change the bios sata setting to AHCI save your settings and boot into windows.

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9 Responses to How to enable AHCI mode for windows 7 and Vista without format.

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  3. Elina Porres says:

    Very interesting. thank you for sharing! You see, I’m currently working on my blog on similar subject to “How to enable AHCI mode for windows 7 and Vista without format. | Bourlas Blog” and I might quote this post in it. I hope you don’t mind

  4. Canon Camera Reviews says:

    I’m not an expert when it comes to this. Didn’t even know this was possible. Useful read, appreciate your posting this.

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  6. Sharky says:

    I thank you humbly for sharing your wdisom JJWY

  7. David Anderman says:

    Concerning installation of AHCI for Windows 7, there is a problem, as Vista drivers may not work on Windows 7 installations, and also, some manufacturers don’t have 64 bit AHCI drivers.

    In my case, I had already wiped my hard drive, and was trying a clean install of 32 bit Windows 7, but the install program would not allow me to proceed – the message was that my main hard drive had to be a system disk. Unfortunately, no configuration of the hard drive, even converting to a basic disk would provoke Windows 7 into installing.

    For Windows 7 to install, the requirements are that the motherboard BIOS be set for AHCI mode (as opposed to IDE mode), plus AHCI drivers for the specific operating system have to be available during install on something other than a hard drive (ie on a USB drive) because once you have set AHCI up in your BIOS, your computer won’t recognize data on your hard drive until Windows Install is functioning.

    So, the bulletproof solution for me was to do a clean install of 32 bit Vista to my wiped hard drive, with my BIOS set to AHCI, and with AHCI Vista drivers on hand. Once Vista started running, I immediately upgraded to Windows 7 32 bit, using Windows 7 AHCI drivers on a USB drive. Everything worked perfectly, as the Install program handled all the registry issues for me.

    Bottom line is that installing AHCI is a requirement for Windows 7, but seemingly impossible without starting off with a Vista install first.

  8. ax5415 says:

    After a catastrophic failure of the hard drive in my HP IQ524 Touchsmart i had to do a recovery from the 3 Disk set with the new Hard drive. Needless to say, the recovery was a flop with default BIOS settings. I changed the SATA controller in BIOS from AHCI to IDE and the install went perfect.

    This Procedure worked perfectly on the Windows Vista x64 version.

  9. Pingback: Windows wouldn’t install on my SSD – change the SSD SATA mode in the BIOS | Captured Bytes

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