Hi there ... I think I've read almost all of the threads I could find on this issue. The solution always seems to be the simple msahci reg fix. For whatever reason, the fix doesn't work for me. I can only boot in IDE.
Booting in IDE isn't a big deal, but I am planning to upgrade to an SSD in the next week and would like to transfer the OS and run in AHCI.
My old mobo tanked. So I purchased a new mobo/cpu and using the SATA drive with existing Win 7 64 Pro OS.
Asus P8Z77-V LK
2 x SATA HD (1 = OS, 1 = storage)
1 X SATA Blu-ray burner
I edit the registry, reboot, set to AHCI, save BIOS . . . and Windows stops loading a Win 7 logo then goes to the repair or start normally screen. Go back to BIOS, switch to IDE and Windows boots no prob. Open registry and the changes I made to the msahci value are still at "0" rather than "3". Even though the drive is in IDE mode?
UPDATE: None of the reg fixes worked, so I used Sysprep and now I can boot in AHCI ... finally. I'll have to reactivate the OS and a few other programs, but no biggie. Now I can transfer the install to a SATA III SSD without running in IDE.