Today we are going to address a very common but one of the most irritating problems in this tutorial.
Consider following scenario:
You got a new computer system in which the SATA hard disk controller mode in BIOS settings was set to IDE ( or IDE Compatibility or Standard IDE) instead of AHCI (Advanced Host Controller Interface) or RAID for better compatibility. You didn't notice that and installed Windows. After sometime you realized it and changed the SATA mode from IDE to AHCI or RAID in BIOS and BOOM!!! You made your Windows crashed. Windows will no longer start and will show a BSOD (Blue Screen Of Death) containing error code "STOP 0x0000007B INACCESSABLE_BOOT_DEVICE".

Why??? Because Windows can't load the new drivers for AHCI or RAID interface. Actually when Windows is installed, it automatically disables unused storage drivers to speed up Windows startup process.
As a temporary fix, you can reset the SATA mode from AHCI or RAID to IDE in BIOS but you'll find yourself in the same situation. Or you can reinstall Windows but that would require lots of time and efforts.
Then how to switch SATA hard disk mode from IDE to AHCI or RAID in BIOS after installing Windows so that you would not need to repair or reinstall Windows?
Here is the solution! You just need to tell Windows that hard disk mode is going to change upon reboot using Windows Registry and Windows will automatically detect the mode and will install the required drivers and you'll be able to successfully change the SATA mode in BIOS without any need to reinstall Windows.
So without wasting time lets start the tutorial:
1. First DO NOT change SATA hard disk mode settings in BIOS, leave it to the default settings which were used while installing Windows.
2. Now start Windows and type regedit in RUN or Start Menu search box and press Enter. It'll open Registry Editor.
3. Now go to following keys one by one:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\pciide
In right-side pane, look for a DWORD "Start". Double-click on it and set its value to 0 (That's zero and not alphabet O).


4. If you are using RAID or other interface, do the same thing for following key as well:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\iaStorV
In right-side pane, look for a DWORD "Start". Double-click on it and set its value to 0 (That's zero and not alphabet O).

5. That's it. It'll reset the hard disk mode settings in Windows registry. Close Registry Editor and restart your system.
6. Now enter into BIOS settings and change SATA hard disk mode to AHCI or RAID according to your requirements.

7. As soon as Windows will start booting, it'll automatically detect the change and will install the appropriate drivers. Once the drivers are installed, Windows will boot without any problem and you'll not need to reinstall Windows just to change SATA hard disk mode.
PS: If you don't want to edit the registry manually and want a ready-made registry script to do the task automatically, download following ZIP file, extract it and run the extracted REG file. It'll ask for confirmation, accept it:
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Posted in: Troubleshooting, Windows 7, Windows Vista
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Richard Adam
I just installed an Intel 520 240gig SD into a Dell Studio XPS 435MT computer. Changed msahci, pciide, laStorV starts to 0. Set SATA to RAID in BIOS. Windows 7 won't start. I'm thinking Windows 7 cannot find the right driver.
Any ideas?
Thank you.
Richard
nick
I dont have the msachi folder, WHAT SHOULD I DO?
Gopal
In BIOS , there is no option to change SATA mode .
Help me.
Jon
Seconded^
sami
problem for me i change hard disk divaice for system AHACI to IDE after this my lap no display black screen
my lap hp pro book
thanks
Joel Mumm
Much appreciated. Needed to enable this setting for a new PCI sata card. Worked like a champ.
julian
i cant power on the pc, so i changed from SATA to AHCI directly y worked!!!
thanks very much.
Bandhan Islam
VG I don't see the option for changing the SATA option from IDE to AHCI or Raid in BIOS in HP laptop.
(Insyde BIOS).
Manufacter-Hewlett-Packard
Model-HP Pavilion DV6725EE KN111EA#ABV
OS-Windows 8.1 Preview (Vista Preinstalled)
Processor- Intel Core 2 Duo 1.83 Ghz 2 cores
RAM - 1 GB (4 GB Max)
GPU- 511 MB (256 MB dedicated) nVidia Geforce 8400M GS
HDD- 160 GB
VG please reply very soon I wanna install Niresh OS X 10.8.2 on that PC. Niresh is a copy of Genuine Mac OS X which work on PC. So I need to enable AHCI.
Garth Oswald
Brilliant!! Thanks for posting this helpful information.
Atta ur Rehman
i face same to same problem as given above while installing window xp on my hp pavilion dv6 core i3 m350 laptop , still i using window7 but i much need window xp . i am trying to install from about 1 month but that error occure ... so plz plz help me what i should do to solve my problem
sebaz_ri
@VG This works for Vista?
Prabhu.P
Need Solution :
I've Toshiba Satellite U400-112
Bios-Phoenix bios 4.0 release 6.1
HDD Model-Toshiba MK2546GSX
I'm facing the problem that system restart twice and get ON , In ON condition boot manager is not working while press F2 or F12 button. It's processing....
then again i've to restart and change the settings in boot manager SATA Controller AHCI mode to COMPATIBLE,then save/exit.Working fine..
But the problem is,
1) SATA Controller mode get changed automatically from COMPATIBLE mode to AHCI mode.
2) After successfully saved SATA controller settings,three to four days working fine. But again the SATA controller settings get changed automatically.
4) OPTICAL DISK drive is not appearing in the boot manager (Rare case)
Please help me asap..
VG
^^ It looks like a hardware problem. You should ask a technician to check your system.
Mike Rogers
Dell e4310. Main drive was 256GB SSD. RAID (IRRT) was on by default, but I didn't notice.
Dell OEM windows 7, kept up to date, including SP1.
Added 2nd (120GB) SSD in DVD drive bay. All working aside from RAID config menu displayed every boot up, and I was afraid of accidental config changes.
Looking to shut off the RAID. Menu, I changed the disk mode to AHCI and it wouldn't boot.
Found this page, but first I had to get Windows back. Removed second drive, used some disk utilities to ensure the right partition was bootable, and the I was able to use your method - thanks!
Just one question: if it was necessary to set "start" to 0 to get windows to take a fresh look at which driver to use (they were all at 3), shouldn't they change from 0 to some other value after it reboots and reports it installed the new hardware?
kkernel kendrick
exellent dude. it has helped
windows 8 / 8.1 ide to SATA EASY
Run msconfig (right click far left bottom corner of desktop then left click run, type msconfig).
Click boot tab, mark safe boot, restart,
get into bios on boot ,( DEL key most likely ), change to AHCI in BIOS, might also have to change boot order SCSI, save settings on exit. and reboot, Windows boots in safe mode.
Run msconfig again, boot tab, unmark safe boot, restart PC.
PC works fine. Don't mess with regedit you only need to boot in safe mode to fix this, very simple.
AHCI-User
The Microsoft support says:
Locate and then click one of the following registry subkeys:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV
support.microsoft.com/kb/922976/en-us
Marco Davids
Yesss! This was what I was looking for. Perfect, thank you.
Morronic
This worked, thanks :)
Chieftec
Hey man, great help because i have the same problem > if i set AHCI on in bios and start up with xp pro cd i get message it dont see drives ... so i wanna install under standard ide and after that do what u say because i have been told my hard drives needs AHCI on to not damage it ???? But i dont have msahci in my registry, can i make it myself ???? same as iastoreV ... PCIIDE i have in registry ...
shaegelin
Very kind of you to take the time to post this tutorial.
Thank you.
Nylson
Thank you so very much! You saved the day man!!!
Mike
AFTER MANY HOURS OF RESEARCHING THIS..... THESES STEPS RESOLVED MY ISSUE!! LEAVE THEM AS 0.
1.Boot OS DVD
2.Choose the Language Selection.
3.Choose Repair.
4.On the recovery tools choose the Command Line Console
5.Type:regedit
7.Highlight HKEY_LOCAL_MACHINE
8.File > Load Hive
9.Select \Windows\System32\config\system (Backup this first, it's advised)
10.Regedit will ask for a Key name: Name it something like "temp"
11.Located HKEY_LOCAL_MACHINE/temp/Select/Current
12.Searched for every key containing the value “SCSI Miniport” where the "Start" value was a "3" and changed the "Start" value to a "0". (F3 to search next result).
13.Highlight "temp"
14.File > Unload Hive
15.Restart
16.Enter into your OS
The Southern Gentleman
I looked in the registery for those two listing and then did a search for the word >
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci
Funny thing it was not there but the pciide was there and you said to change both of then so one without the other is not going to help me...
jahwisdom
It works ! Thanks a lot
AndrasB
Thank you for the solution!
apr2014
Pepe
Wow! It worked perfect!!!
Erald
please help me!
HOW TO CHANGE SATA TO IDE MODE IN SAMSUNG R730
Charlie
Excellent!!!! Praises be upon you!!! SSD is now seen sans the BSOD!!!
Thank you
Joop Wolf
Fantastic, this is a good working solution. I used it on my Acer desktop PC.
Thank you very much!!!
David F
Brilliant.
Many thanks.
Changed one digit in the registry and suddenly all is well. My SSD is now giving me impressive start-up and programme-opening speed on a seven-year-old computer - without a BSOD every day.
You now have a place of honour in my browser's toolbar.
Name your favourite charity and I'll send them a "thank-you".
William R
Thanks for info. I have an Dell Optiplex 755 running Windows XP Professional. Stopped booting from hard drive. When I try to boot from USB/CD-DVD I get the screen you have shown above. In Boot Set up no option to select IDE only AHCI, ATA and Legacy. When selecting ATA or Legacy get warning that it will mess up the set up. Have reset BIOS to default, run diagnostics on machine and all is good.
How do I get Windows to come up so I can apply your fix if it won’t boot from CD/DVD?
Thanks.
oOo.Manu.oOo
Thank you very much !
Ron
Thanks for posting the explanation concerning BIOS Sata settings. It was helful when performing a recovery of a RAID0 backup image of Vista Ultimate x64 onto a new non-RAID hard disk.
I initially used a BIOS Sata setting of AHCI to optimize the performance of my new 1TB hard disk (replacing a pair of 320GB disks). Vista x64 would not boot.
After setting the K8NE-Deluxe MOBO BIOS to defaults, the non-RAID hard disk now boots A-OK.
Modifying the registry entries as decribed above is now an option.
dannywmp
Hi,
It works for the instant but when I powered off my system and restart it, it will again not boot up to Windows and stuck at updating DMI.
I will then need to go into Bios change it to IDE again before it can goes to Windows 7.
Please help. Thanks