Fixing boot issues related to IDE/AHCI modes with Windows 7

Mar 07, 2017

I pulled this from Tom’s hardware page on how to fix Windows boot up issues related to IDE and AHCI modes. This seems to work for most who try it. I use it to fix this specific issue when restore images or clone an install of Windows 7 made from similar chipsets.

If your system works in IDE mode but not in AHCI mode then the following procedure should solve the problem:

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.

When Windows starts, it will detect the change, load new disk drivers, and do one more reboot to start up with them.