Can Windows 7 boot from an external USB or FireWire drive? [duplicate]

"I have spent a few days looking around for a solution to this and also made an attempt to install Windows 7 on an external drive myself.

Long story short, the answer can be rounded down to ""No, it is not possible to run Windows 7 from an external USB or FireWire drive"".

The rounding error is a few guides employing hacks and workarounds and third-party tools with partial success.

Edit: Links to sites on the topic

Raymond Chen saying it isn't possible

Tom's hardware guide, 14-step process using BartPE and other tools

Another site using VMWare and a registry hack"

"I've been researching this for the last week, and, from what I can tell, Windows has to install on a ""fixed"" disk. USB devices show up in Drive management as a ""removable"" disk.

Lexar has a utility that will flip the ""removable"" bit on a USB device, but so far I haven't been able to use their utility to flip the bit on any USB drive. I'm out to buy a Lexar drive to test this, but as of this post the answer is still ""no, you can't install Windows 7 on a USB drive"". Hopefully, this afternoon's testing will prove different."

"I can confirm that it's possible: I did it over the weekend.

It takes around 30 minutes, but done from CMD. One needs to log-in diskpart to do that, clean the disk, format. You would require a Windows .iso file, and a virtual disk to transfer the image from C: to the removable drive."