Sometimes a computers BIOS has the option to choose between different modes of storage access. Windows does not automatically handle you changing that mode to something different from when Windows was installed without some 'user intervention'.
I use to change Dell computers default from RAID to AHCI. But quickly found that if the BIOS resets to default for any reason (eg: CMOS battery failure and power outage) then Windows will BSOD with an "Inaccessible Boot Device" error.
This is the procedure for getting Windows to recognise when you have changed that storage mode and activate the correct driver:
- Run cmd.exe as administrator
- Invoke a Safe Mode boot with this command:
bcdedit /set {current} safeboot minimal - Restart the computer and enter the BIOS at BOOTUP.
- Change your storage mode eg: RAID to AHCI.
- Save & Exit the BIOS.
- Windows will now launch in Safe Mode. In Safe Mode Windows detects you have changed storage access mode and activates the correct driver..
- While still in Safe Mode run cmd.exe as administrator again.
- Cancel the Safe Mode Boot with this command:
bcdedit /deletevalue {current} safeboot - Restart your computer once more and it will start with the correct Storage mode driver activated.