Change to AHCI mode after Install - Windows 7?

Rezident · 30 Jul 2015 at 12:56

Installed Windows 7 but forgot to switch to AHCI in the BIOS (for SSDs). Found a few fixes such as:

1) Run the Registry Editor (regedit.exe)
2) Navigate to Registry Key: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
3) Set the "Start" value to 0 (zero)
4) Navigate to Registry Key: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Pciide
5) Set the "Start" value to 0 (zero)
6) Shut down
7) Start up again, but before Windows boots go into the BIOS configuration screens and change the disk mode to "AHCI". Save the new BIOS configuration and restart so that Windows boots.

Some of the fixes do not include the ‘pciide’ line above, some others have a different one added:
- HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV (In case you have the intel drivers)

Do you have to do the pciide one (and IastorV) or just the Msahci?
Or is there an easier way to do it than fiddling with the registry?

varkanoid · 30 Jul 2015 at 15:32

Yes do a search for Microsoft AHCI Fix it.

MadMatty · 30 Jul 2015 at 17:28

You don't ever need to mess with registry. Just install the ahci drivers and you are good to go. Windows will detect and re install the correct driver whenever you have changed the bios setting.

Rezident · 30 Jul 2015 at 18:03

Ok ran the MS fix, checked changes had been made, they had, rebooted, changed IDE to AHCI in bios, and windows will not start anymore, black screen. Changed back to IDE in bios and windows still will not start.
I actually knew this would happen. Anyone know what is wrong now or how to fix it?

Rezident · 30 Jul 2015 at 20:42

OK so Windows cannot start by itself now. However, when I put the Windows 7 disk in, it does start, but without restoring or repairing anything :confused:

The drives are now in AHCI mode but Windows cannot startup without having the Windows 7 disk in, how do I fix this? Repair Windows or something else?

Rezident · 31 Jul 2015 at 10:21

OK windows 7 disk was able to repair Windows but the Microsoft Fit it thing definitely broke something. Think it's repaired now, fingers crossed.

tomtalk24 · 31 Jul 2015 at 15:07

Rezident said:
OK windows 7 disk was able to repair Windows but the Microsoft Fit it thing definitely broke something. Think it's repaired now, fingers crossed.

Any luck? I remember I needed to reinstall Windows when changing from IDE.

kitch9 · 31 Jul 2015 at 19:19

Easy.

Tell windows to boot into safe mode, reboot.

Make the change in bios.

Boot into safe mode, then reboot.

Job done.