Correction. There *must* be a space between bcdedit and the forward slash. There is no command called "bcdedit/set" (for good reason)

Good information and thank you - it worked nicely. :)

this works, thanks

I used the ALT commands

This approach worked on my Windows 10 machine - which should have been set up with AHCI in the first place since all of my drives are SSD. However one must know that it may take several reboots for your D: disk to re-appear and become stable. In the first reboot, my data appeared to have been lost. After swearing at the computer several times, I decided that perhaps a reboot would help the situation. Fortunately after 2 more reboots, the disk re-appeared and all of the data was intact.
Thank you for these steps to switch my computer from RAID to AHCI.

Added a Samsung 970 Evo (500GB) NVMe M.2 alongside the existing HDD in new Dell Inspiron 5570. Samsung software couldn't load the drivers because drives configured for RAID. I set AHCI in BIOS and W10 (home) wouldn't boot up. Returned to BIOS to RAID and rebooted successfully. Found this thread and tried it. Yes, it worked! It took a bit of work to manipulate the the drive letters afterwards but got there eventually. Thank you for the information.

I had a really odd experience attempting this on Windows 10, but I finally figured it out:
When I switched to AHCI and got to the safeboot menu, my keyboard wouldn't work. If I tried to get to the keyboard settings nothing happened. I was able to get to the Command Prompt terminal via the 'Windows Systems' tab in the Start Menu. Once I had opened the Command Prompt, I could type in it using the on-screen keboard (Start Menu -> Settings -> Ease of Access -> Keyboard (scroll down and it's on the left) -> On-Screen Keyboard). Then I typed bcdedit /deletevalue safeboot (there didn't seem to be a way to use curly brackets). Then I Rebooted, and found that I had left Safe Mode, and everything was back to normal :)

It's one hell of a work-around, but hopefully this helps somebody!

Thanks @Evan! The keyboard thing also happened to me, but using the virtual keyboard did the job. If you press the shift key you'll be able to use curly brackets!

Thank you very much! I am running Server 2016 and didn't realize my Intel board was in IDE until I tried to run two SSD's in Raid0 and was only getting about 400MB/s. I switched to AHCI and was getting "Inaccessible boot device". I used the method described above and it's working now! 1100MB/s.

Worked perfectly on a Dell Inspiron 15 7586. Came pre-configured in RAID mode and updated to 970 EVO Plus without the ability to get the Magician to function.
As soon as I completed the operation which took about 3 minutes, everything worked perfectly with no glitches or issues

Saved my day. Alternative command is somewhat confusing. I used bcdedit /set {current} safeboot minimal and bcdedit /deletevalue {current} safeboot
Result is that W10 booted with sata settings set to AHCI, Happy!

Thanks for sharing!

Saved my bacon!
I got my ageing (10yrs) Dell T5400 back into life using the full commands.

Very many thanks!

Just performed the procedure on an old Dell D630 fitted with a Kingston SSD that didn't have AHCI enabled.
Went flawlessly and machine now seems to boot a little quicker and feels quicker in operation.

Many thanks!

This worked for me! Thank you, thank you, thank you.

At some point my intel RST drivers stopped, and I was unable to reinstall the drivers. I thought it was a windows 10 1903 build issue however my system was still on 1809. The problem was at the BIOS level. Some how either through a BIOS update or a dead battery the BIOS storage configuration changed from RAID to IDE.

Without RAID enabled in the BIOS the RST drivers will not install. Also be sure to select the correct driver for your chipset. The newest drivers are not fully backwards compatible!

However even if I manually installed the RST x64 drivers first and then changed the BIOS to RAID the system would not boot.

I opened windows disk management utility and confirmed that the RAID 1 array was broken. Both disks appeared in the drive list, with one showing a warning due to addressing conflict (oh no)

Steps
1) installed the newest intel RST x64 driver that supports the chipset
2) set safeboot per above
3) enabled RAID in BIOS (was IDE)
4) booted to safemode
5) removed safeboot per above
6) checked that intel RST is running YES!
7) verify RAID 1 array (no idea how long the array was broken)

run windows disc management tool and verify RAID now appears correctly as 1 drive

After this Through some update cycle windows stealthily replaced all of the chipset and storage drivers with generic MS drivers.

I hope this helps someone else

to enter bios is a separate step. On my PC it is hitting "DEL" key during reboot.

Awesome. This worked.

(ALT: bcdedit/set safeboot minimal). No space between bcdedit/set

Worked perfectly on a Dell XPS 13 9360 (i7, touchscreen, SSD). Stupid question: Why doesn't the WIndows automatic repair do this?

This article is a LIFE SAVER!!!!! I'm in the process of migrating a new Windows 10 installation from a 2TB HDD to a 1TB SSD. This is a new (refurbished) Acer desktop system that came with RST with Optane configured in the UEFI settings. So, I followed the steps to switch it to AHCI and Windows 10 now boots. I'm now off to re-clone the HDD to the SSD. :)

For those having problems running the bcdedit commands, the "ALT" commands are supplied as *alternate* commands to use. So, either run the bcedit command that appears *before* the parentheses or run the command INSIDE the parentheses, but not the commands as shown above.

For me, I ran these commands:

bcdedit /set safeboot minimal

(then I rebooted and switched to AHCI)

bcdedit /deletevalue safeboot

THANK YOU for writing such clear and accurate instructions!

Peace...

Worked flawlessly, thank you!

It's 2a.m. God bless you.

@Tom williams thank you very much for better explaining this tuto !
because it did not work because of ALT in the tuto!
and i confirm : it woooooooooorks !!!!! :-D

I have an asus Z97-A motherboard and Intel rapid storage technology is automatically activated in my bios and it automatically activates RAID and i didn't want to.
I wanted AHCI. Every time i reselected AHCI, i had a blue screen crash !

Thanks to this great tuto i can finally! :) i did not believe it and yet it works perfect!
I will see if the file transfers are accelerated in writing with my SSD samsung 850 evo 250go :) because before in RAID i never exceeded 80mb/s for files of 20 - 100go approximately when my ssd can go much higher...

I cloned a normal HD onto an SSD, so the setting was at ATA in the bios. Windows ran fine with ATA setting booting from the SSD. I booted normally into Win10, set the safemode, rebooted and changed the BIOS setting to AHCI and booted. Win10 booted into safe mode. In there changed the setting back to normal boot and now its running in AHCI mode.
Awesome! Thank you!

Este autor se merece una ceveza bien fria.

Thank you a lot.

Worked like a charm!
Shukria :)

PERFECT! I was trying to install Linux Mint 20 on a brand new laptop that was running Intel RST by default. Linux couldn't install while RST was enabled, your command prompts and easy instructions in the BIOS made this a breeze. Thanks!

thank you so much

Worked perfectly (used the shorter ALT commands) on my 12-year-old system that, with SSD and a few other upgrades along the way, is still running fine.

I have been trying to dual boot a Dell 5593 laptop with Windows 10 and Linux. If I set disks to RAID, Linux won't load. If I set it to AHCI, Windows won't load. This cure has at least got me part of the way there. I can now boot Win10 in AHCI mode. Now all I have to do is get the machine to boot into the Linux memory stick and take it from there. Thanks to all of you guys who take the time and trouble to help out the rest of us. Give yourself a pay rise.

Thank you - with your instructions I was able to install Ubuntu 20.04 on a new Dell XPS 17 9700

Thank you, this made my Ubuntu installation on my Dell Inspiron 5400 so easy, after i had almost broken my Windows lol
Perfect tutorial

I used the alt and it worked completely fine, going from IDE to AHCI.

Sorry for the previous comment.

It works perfectly!

hi kids
/set parametr in bcdedit return error

i did it much simpler

- to enable F8 key (safe mode) use command
(In win 10 Build 1909 or leter)
bcdedit /set bootmenupolicy legacy

- in Windows control panel / system /device menager / remove the hdd drive with system and confirm reboot
- ater reboot go to BIOS setins and set the AHCI mode save setings and exit bios
- next reboot go to safe mode command prompt by F8 key
- in safe mode command run chkdsk /f and confirm ( i dont know if its nesesary but i did the step)
- reboot system by CTRL+ALT+DEL
- done
sorry for my language (i don't know english)

So AWESOME!!! Thanks!
Had an "Oh Bugger!" moment when I realised that I had installed Windows 10 to a new SSD in IDE mode.
Saved the above instructions to a txt file on the desktop for copy and paste into cmd prompt purposes, and it all worked a treat. This saved me a heap of time not having to re-install all over again.
Many praises.

Thank you sooo much! This worked too well to be believed.

P.s. done that.
Removed second part of command ALT
And everything finished perfect!

Thanks a lot for the livesaver trick!!!

Going to try it again. I'd suggest though, at least from what I experienced last night is to make sure you use an admin account that isn't linked to a MS account password online. Wouldn't boot into Safe Mode with Networking no matter what i did. I had to create an install disk on another computer, start to reinstall just to get to a cmd prompt. I wound up creating a password-less admin account on cmd line which enabled me to delete the safeboot mode value. Gonna try again tonight with the new account!

Worked a charm without any hiccups whatsoever, BRILLIANT!

There is one thing I want to ask about this.
I checked in my Device manager and there isn't an option like IDE ATA/ATAPI controller aka I am not able to find any SATA controller or something. Would this technique work even if these controllers aren't present? Will it install these drivers automatically once I change mode?
Model - Lenovo Ideapad S340, 1TB HDD + 256GB SSD.
Basically, I want to install Ubuntu, which I am unable to do because of RST mode. And I don't want to lose Windows.
Rest, I am convinced this technique works.

It worked, so awesome, thank you so much. I struggled over this for hours and tried a bunch of things from other websites, none of which worked.

how to i start in bios once i reboot?
system does boot in safemode

Ok. I decided to bite the bullet and it worked for me. Though the BIOS gave some notification that my disk will be erased if controller mode is changed, still changed it to AHCI mode and booted according to the steps above and it worked. No data lost, everything works fine. This piece is a savior.

Dual Booting my new Acer Aspire A515-55.
Thanks for this great tutorial. I am a long-time Ubuntu/Linux user and fan. I have been using a Toshiba that was released with Windows Vista (long gone) on it. I bought a new Acer Aspire A 515-55. Imagine my distress in finding that not only could I not dual boot, but the Acer factory install of Windows 10 with RAID/RST would not let me load Ubuntu at all. My pre-purchase research did not uncover this problem.

I found several work-arounds on the web, but while the others were clear about the problem, they were not as clear on how to solve it. Each manufacturer, it seems, was a little different in how to reset from RAID with RST to AHCI. I was fearful I would turn my new machine into a boat anchor. Your tutorial saved my investment. Ubuntu 21.04 is working fine along side of Windows 10. I used the alternative edits.

My Microsoft Surface Studio has UEFI not BIOS and I can't find a way to do what is done here in BIOS. This is stopping me from installing Ubuntu.

Hello!
I need help!
I was trying to performe this and got stuck on first reboot!
The PC starts but I get nothing on the screen!

Unfortunately, it is not working on my laptop, at the moment.

I own a Dell Inspiron 17 5770 and I have the OS installed on a M.2 2880 NVME SSD (Crucial P5) plus the original 2.5 HDD; everything is working perfectly with this setup.

The problem comes when I substitute the original HDD with a Crucial MX500 (2TB) SATA 2.5 SSD, which I have recently purchased and wanted to use as a secondary storage unit.

Despite I have initialized, cloned, allocated and formatted it several times, and then changed SATA Operation from RAID to AHCI, it doesn't work.

I mean, the 2.5 SSD is sometimes visible after booting, but it disappears in a few minutes, or as soon as you try to use it.
If you try to paste something or to make any operation on it, the PC gets very slow or even crashes sometimes.
Once desappeared, the system does not detect it in the Disk Management either.

The only two situations in which the drive is visible are:
- when I plug it from an external SSD case, via USB;
- when it is set as the main storage and boot unit (cloned from the M.2 SSD).

However, the problem is that I want to keep the M.2 as the main storage unit and use the 2.5 SSD as a secondary one, but I don't really know what else I can do to achieve that.
Could anybody help me with that issue, please?

Tried and worked on Windows11

@Gianni. You need to conduct two steps. (1) change raid to non raid using above method and (2) then cloning the drive. Cheers Michael