Changing from RAID to AHCI


on my Dell E6510 I have my disk drive set to RAID mode. I have issues using the eSata port so I want to switch to AHCI. I followed the instructions here: However when I boot my system after setting the disk mode to AHCI in the BIOS I see the Windows logo (using Win7 x64) and some seconds later I get a bluescreen with a message I can't read because the system is rebooting. Changing the BIOS back to RAID brings up the system again...

Anything I can do to make AHCI working?


Thomas Pagel

Question Info

Last updated April 7, 2020 Views 174,652 Applies to:

Hi Thomas,

Thank you for your post.

I believe I have the solution to your problem and I verified it against a Dell machine that has similar controller with your machine. Changing from AHCI to RAID, fix will work.  

Changing from RAID to AHCI, you need one more step. Msahci driver requires Atapi.sys miniport to be loaded during boot as well. So you need to change theStart value to 0 for both of the following entries in your registry. You can use regedit.exe utility. 


Or you can also simply run the below command lines in an elevated window.

REG ADD HKLM\System\CurrentControlSet\Services\msahci /v Start /d 0 /f /t REG_DWORD
REG ADD HKLM\System\CurrentControlSet\Services\atapi /v Start /d 0 /f /t REG_DWORD




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