Windows – Switching IDE to SATA with VirtualBox and Windows 7

I encountered this exact error when moving a physical Windows XP installation with a SATA controller to a virtual IDE controller (because I could not get my Windows XP iso to boot with the SATA controller and do a repair operation).

The catch is that Windows XP only registers specific controllers during install, which is why you can't switch from an IDE controller to a SATA controller (or vice-versa) without repairing the installation. However, instead of repairing the installation, you can also manually add support for the SATA controller to the Windows registry.

To fix this:

1. Download the MergeIDE tools hosted by VirtualBox here
2. Boot into your Windows XP install with an IDE controller
3. Apply the MergeIDE.reg file to the system registry.
4. Shut down the VM and switch it to a SATA controller.
5. Start the VM back up.

This particular instance of the 0x7B stop code is documented by Microsoft here, and the fix is documented by VirtualBox here.

--discard options specifies that vdi image will be shrunk in response to trim command from guest OS. Following requirements must be met:

• disk format must be VDI
• cleared area must be at least 1MB (size)
• [probably] cleared area must be cover one or more 1MB blocks (alignment)

Obviously guest OS must be configured to issue trim command, typically that means guest OS is made to think the disk is an SSD. Ext4 supports -o discard mount flag; OSX probably requires additional settings as by default only Apple-supplied SSD's are issued this command. Windows ought to automatically detect and support SSD's at least in versions 7 and 8, I am not clear if detection happens at install or run time. Linux exFAT driver (courtesy of Samsung) supports discard command. It is not clear if Microsoft implementation of exFAT supports same, even though the file system was designed for flash to begin with.

Alternatively there are ad hoc methods to issue trim, e.g. Linux fstrim command, part of util-linux package.

Earlier solutions required user to zero out unused areas, e.g. using zerofree and compact the disk explicitly (I'm assuming that's only possible when vm is offline).