Installing windows bootcamp external HD rMBP

[Arpetee]

Hey all,
I'm aware you are able to install Windows via a usb stick through bootcamp, however my question is whether you are able to install it from a USB external hard drive. I've loaded up a Windows 8 .iso on to my WD My Passport and tried to get it going through bootcamp, but every time I try I get "Your bootable USB drive could not be created."

I have made sure the image is not mounted. Any ideas? Does it just not work on an external HD and have to be a flash drive? Thanks.

 

[swerve147]

If I recall correctly the external drive needs to be seen as a SATA device (i.e. it can't be USB). Essentially only a Thunderbolt drive can be used as a bootable drive into Windows. The process requires a small boot partition to be kept on the internal HDD/SSD but it can be done.

I'm sure someone will correct me if I am wrong.

EDIT: Here you go:

https://forums.macrumors.com/threads/1497778/

 

[Arpetee]

I'm not actually trying to install W8 ON the external drive. I'm trying to install it internally, just install it OFF the external. Exactly like one would do with a USB Flash stick. I just don't have a stick bigger than 4gb convenient.

 

[Arpetee]

Ok this is beginning to get quite frustrating. No one has any ideas?

I've tried 2 different .iso's, my external HD, and a USB stick now as well. Same problem every time. Any input would be greatly appreciated.