WARNING: Windows and AHCI (Advanced Host Controller Interface)
 

I wanted to upgrade the software in my SSD but it would only work if the SATA drives were set to use AHCI (Advanced Host Controller Interface) in the motherboard BIOS (it was set as IDE). So I edited the Win7 registry to use AHCI and changed the BIOS to AHCI, on rebooting I was able to flash the SSD no problem.

A side effect of using AHCI is that all SATA drives become plug and play, including your boot drive and other internal drives. They are added to the 'Safely remove Hardware and Eject media' tray icon.

Being curious I tried to eject my Data HD (a separate 1Tb Seagate hard drive, not a partition on my boot drive which is a 50Gb SSD), it was removed from the list but was still accessible.

On reboot later I got:
Bootmgr missing
Ctrl+Alt+Del

I tried using the Win7 install DVD to recover the missing file but that didn't work, luckily I'd made a full backup image of the whole SSD drive before I flashed its BIOS so I was able to boot the Paragon recover CD and replace the MBR & OS etc.

The motherboard BIOS is back to IDE. ;)

Re: WARNING: Windows and AHCI (Advanced Host Controller Interface)
 

Hmm, that's not right. I've got ACHI switched on for my laptop and the SATA drive doesn't show as a removable drive.

I think its probably the hacks you did to enable it that caused the problem

I always thought that it's always a bit tricky swapping from IDE to ACHI after install - even on Windows 7

Re: WARNING: Windows and AHCI (Advanced Host Controller Interface)
 

no if ACHI is correctly installed then yes it is hot swappable all the hacks do is enble ACHI in the registry so it will work at all . Quite simple

To hot swap drives the controller needs to be ACHI compatible as does the power supply cables.

I would assume your chipset is not fully hotswap capable? You should never just pull a drive if caching is enabled

Re: WARNING: Windows and AHCI (Advanced Host Controller Interface)
 

What I don't understand is why just soft unmounting that drive should brick the Win7 install (which as I said was on another drive), nothing physical was done while the computer was switched on as the drives were all inside the tower.