In my case, I initially had trouble with my BIANCA external HDD installation.
I believe (I can`t remember for sure, but I think I did) I had my internal drives connected,
but the "live CD" installer would only get as far as 15% and then fail at most of my early attempts.
Or, I would get further on, but then stall or error messages somewhere along the way.
This was frustrating to say the least, but I perservered.
I tried several completely *different* install variations, but would get error messages etc. Finally I think I ended up having to first *unmount* my external USB drive,
which later (during the install), showed up on the "LiveCD" desktop again, though this time labled as: *TARGET* !!
I also somehow ended up installing to: (hd3,0) just for a successfull install to the USB drive, but then when booting up, GRUB couldnt find the install!
Grub did however, list several options including EDITING (press"E").
I edited GRUB from (hd3,0) to *(hd0,0)* and it would FINALLY boot to my Mint BIANCA install!!
This worked fine, but I would have to do this edit each time I booted up!
Later on while in BIANCA and at the command line, I permanently changed GRUB from (hd3,0) to (hd0,0) using first: sudo gedit /boot/grub/menu.lst
Backspacing the unwanted line(s) and adding the new.
I hope I`m not confusing you? I`m just trying to remember any pertinent information.
I dont know if I just stumbled my way into a successfull USB HDD installation of BIANCA or what ?
Mind you, I did NOT have any of this with my Cassandra installation, as everything went smooth and efficiently as I described in my earlier post,
though as I have said, I did pull the power cables to all internal drives before the install.
Hope this helps?