Switching SATA Mode from RAID to AHCI

[azhe]

While dealing with another issue, I've been told that I should switch my SATA mode from RAID to AHCI. I do not have a RAID array and don't plan to. However, I've been told that I would need drivers for this, and I'm not sure if my Windows installation has them or not. I don't want to switch modes only to boot Windows and have it corrupted or god-knows-what. So could someone tell me if it's possible to just switch? Or should I check for drivers first?

 

[TwoCables]

First of all, is it really currently set to RAID mode in the BIOS?

 

[TVeblen]

Your Windows installation has them, but they must be activated.

The procedure is really no different than changing from IDE mode to AHCI: you edit the Registry to activate AHCI driver, reboot and go directly into the BIOS, change the SATA mode to AHCI, and then start back into windows. But there is one extra step.

Change from IDE here:
http://www.sevenforums.com/tutorials/61869-ahci-enable-windows-7-vista.html

Change from RAID here (scroll down to "let me fix it myself")
Error message occurs after you change the SATA mode of the boot drive
Note that you may need to change the IastorV key to 0 instead of msahci.

Note that it says you must change ONE of the values to 0. That should be Msahci. IastorV is Windows RAID driver.

 

[azhe]

First of all, is it really currently set to RAID mode in the BIOS?

In BIOS I see Storage->Storage Options->SATA Emulation, set to RAID. So I assume so. Furthermore I've seen messages on my computer regarding RAID (which I do not use).

Change from RAID here (scroll down to "let me fix it myself")
Error message occurs after you change the SATA mode of the boot drive
Note that you may need to change the IastorV key to 0 instead of msahci.

I did as the article said, and each time it bluescreens on boot. I tried enabling msahci, then vice versa, and it doesn't work. It will still only boot in RAID mode.

Is there another step I missed? All I did was edit the registry, then change the mode in BIOS. Is there something else that needs to be done to enable them?

I don't know if a memory dump was created from the crashes, but if it would help I could post them if you could tell me where to find them.

 

[azhe]

I apologize if double-posting is bad, but I have more information that might help. I'll edit my post from now on if that's what I should do.

Would Windows fail to boot (as it did) if the drive had some kind of RAID metadata on it? I just ran a command (sudo dmraid -r) in Linux that gives me this:

/dev/sda: pdc, "pdc_bbhjjee", stripe, ok, 1953124992 sectors, data@ 0

sda is my Windows drive, the drive that shipped with this PC. HP advertised it as "RAID Ready," even though it didn't come with a RAID.

I'm pretty sure it's possible for me to remove this data via Linux, but would that cause any harm to my Windows installation? I don't want to do it if I can't boot to Windows afterwards.

 

[TwoCables]

I'm not sure, but I know that the values for the subkeys below all have to be 0:

• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\msahci
• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\iaStorV
• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\iaStor

 

[azhe]

I removed the RAID metadata on the drive and it works fine. So that is not the problem.

I'm not sure, but I know that the values for the subkeys below all have to be 0:

• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\msahci
• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\iaStorV
• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\iaStor

Setting either or both msahci and iaStorV to 0 results in a bluescreen after switching to AHCI mode. I do not have a iaStor key. Seeing as my other problem has been solved in spite of this, would it be okay to leave this as is? Or is very important that it be in AHCI mode?

 

[bassfisher6522]

Is the PC you talking about the same one listed in your "My System Specs"? If so, then I should think that the factory settings for it would be optimized as far as drive modes go. Unless you added another drive to the system or an SSD and needed to change the drive modes, the SATA mode should be the default setting and should be just fine.

Otherwise, in order to switch to RAID mode or AHCI mode, those drivers must be installed and enabled before the OS is installed otherwise you will get those BSOD's and a reinstall of the OS is required. Basically, the AHCI mode is needed if you're going to install a HDD greater then 2TB or an SSD. IDE mode, is basically for legacy drives

I've not used TVelben's suggestions on editing the registry and rebooting. Nice find btw TVelben, I've only installed the drivers, enabled it in the BIOS and the set boot order for cd/dvd, reboot then format and clean installed.

 

[TVeblen]

I too have always set AHCI first and then installed Windows. I only had to change from IDE mode once on a repair. And the process went off without a hitch. I have never tried it from RAID mode. I can't image why it won't work.

Perhaps the driver files are not included in an HP customized install (except, why would they do that?)

Bottom line: if it ain't broke don't fix it. The RAID driver is very often the same as the AHCI driver anyway (not always, but common - I've seen a few download sites that only offered an AHCI/RAID driver, not one or the other). So if everything is working as it should then you could just leave it.

Why are you being told you need to change it?

 

[essenbe]

The OP has an AMD CPU so would not have an IaStor setting. IaStor is Intel's AHCI driver. If he is set up in raid mode, his installation is striped. If he actually is running raid, his only option is to reinstall in AHCI mode. A screenshot of disk management should tell whether he is in a striped array. http://www.sevenforums.com/tutorials/274797-disk-management-post-screen-capture-image.html
But, as TVeblen said above. If it is in raid and running OK and there is no compelling reason he needs to change, let it stay the way it is. If the time comes to reinstall, he can change it then.

 

[azhe]

Why are you being told you need to change it?

There was no specific reason given. This was on a Linux forum, so maybe it has to do with that system. Although it hasn't caused me any problems as far as I can tell, so still I don't know why. Maybe he figured it had to do with another problem I was having, but that's since been solved.


I suppose I'll let this thread die. Should I mark it as Solved even if I wasn't technically able to switch (the point of this thread)?

 

[TwoCables]

Why are you being told you need to change it?

There was no specific reason given. This was on a Linux forum, so maybe it has to do with that system. Although it hasn't caused me any problems as far as I can tell, so still I don't know why. Maybe he figured it had to do with another problem I was having, but that's since been solved.


I suppose I'll let this thread die. Should I mark it as Solved even if I wasn't technically able to switch (the point of this thread)?

Yeah, I would. I mean it's like you said, it's working perfectly right now, so I see no reason to change anything.

 

[TVeblen]

I don't know. If you mark it solved then someone coming along later looking for an answer to do the same thing will not find that answer here. I think it should be marked solved if it is solved.

 

[Gswiss]

FYI, there is a solution which addresses directly and simply the switch from RAID to AHCI as indicated in the topic, without a reinstallation of W7.

If you go to the page Error message occurs after you change the SATA mode of the boot drive, you’ll find Microsoft Fix it 50470. Just execute this module under Windows 7, reboot, switch RAID to AHCI in the BIOS and Windows 7 will then boot with no BSOD.

Nothing else is required, just another reboot.

 

[paradisca1]

I have a related post. My new Dell Precision T3610 came with BIOS in RAID SATA mode. The msachi start value was set to 3 which confuses me. I switched BIOS to SATA AHCI expecting a BSOD. It booted fine and a check of the registry shows following start values: msachi = 3, IastorV = 3, Pcide = 0, Atapi = 0. Intel RST says everything is fine and I am enjoying advanced SATA features. It all seems contrary to what I've read here and in Microsoft KB.

 

[TVeblen]

Hello paradisca1. Welcome to the forum.

That is quite strange. I certainly can't explain it.
Does that system use the new UEFI bios?

 

[paradisca1]

Thanks for your attention.

It has the uefi option in the BIOS setup but I've left it at the default Legacy (MBR) mode.

 

[essenbe]

If you install in IDE mode and switch to AHCI, it will BSOD because the install was in IDE mode, so the OS does not include the AHCI drivers. If you install in Raid mode and install Intel rapid storage technology (Intel's Raid driver) the IRST includes the IaStor AHCI driver. So, when you switched the mode to AHCI, it already had the AHCI drivers, so it booted. The fix to change from IDE to AHCI is a registry change in an attempt to force the OS to install the AHCI drivers. You already had them. That's the way I understand it anyway. IRST is the only way to get the IaStor.sys driver that I know of.

 

[paradisca1]

Thank you, essenbe. So if I now switch BIOS to SATA ATA it should boot in ATA mode, right? And if I then go into the registry I should find HKLM\SYSTEM\Services\msahci with a value = 3, right? And if I now set that value to 0 and reenter the BIOS and set the SATA mode back to AHCI and boot it should reinstall msahci.sys and then reboot into AHCI mode, right? I hope I have it right.

 

[essenbe]

Thank you, essenbe. So if I now switch BIOS to SATA ATA it should boot in ATA mode, right? And if I then go into the registry I should find HKLM\SYSTEM\Services\msahci with a value = 3, right? And if I now set that value to 0 and reenter the BIOS and set the SATA mode back to AHCI and boot it should reinstall msahci.sys and then reboot into AHCI mode, right? I hope I have it right.

I understood you to say that you had changed it to AHCI in bios and it booted. Was I wrong? If I was right, you are already in AHCI mode, or should be. Go to device manager and post a screenshot of an expanded IDE ATA/ATAPI Controllers. (http://www.sevenforums.com/tutorials/9733-screenshots-files-upload-post-seven-forums.html).