I was playing around with the new 1.6.2 Sun branded VirtualBox and thought I would clone one of my existing VDI's to a new one and then setup a new VM to use that VDI to play with.

So the first thing I did was clone the VDI using the cmd tool that comes with VirtualBox:

C:\Program Files\Sun\xVM VirtualBox\VBoxManage.exe C:\users\steven\.virtualbox\vdi\foo.vdi C:\users\steven\.virtualbox\vdi\bar.vdi

Nifty. Worked like a charm. Then you just go into the VirtualBox Virtual Disk Manager and add the newly cloned bar.vdi and then setup a new VM as usual to use that VDI.

But then of course it didnt want to boot Windows, just a series of lovely BSOD and reboots. Joy.

I trolled around on the forums and found that Innotek (or I guess Sun now) changed the default IDE controller from  PIIX3 to PIIX4 and this change seems to make Windows XP very unhappy. Go into the VM under the Advanced tab change from 'PIIX4' to 'PIIX3'. Now it boots. 

My only real compliant with VirtualBox is, well ok my only two complaints are; 1. Virtual Networking is a real PITA and 2. Why not have a UI for all the awesome options found in the
VBoxManager.exe utility. Ah hell the price is awesome, and I get great
USB support (boo! no USB device support for Virtual PC) and I dont have to download a 125MB download and register (boo! VMWARE).

Enjoy!