Tin Cups and String: The Convergent Microsoft UC Blog

I found myself wanting to boot from a USB flash drive, and not just boot a utility OS, but to actually have a USB drive that would install the Windows Server 2008 R2 OS.

With the help of my good friend Google, I found a quick and easy way to do this over at Tom’s Hardware. Some said it wouldn’t work, some said it would, so I gave it a try and I had zero problems.

So…here we go. Hopefully someone finds this useful, and at the very least I’ve confirmed the process works.

First things first, you’ll want to use a machine that has diskpart. Vista, Win 7, Server 2003 and above all have this utility, just open up a command prompt (as Administrator, depending on your settings) and type diskpart

Once you’re inside the diskpart utility, you’ll want to type:

list disk

On my particular machine, the USB flash drive I was looking for was disk 10. Usually you can determine which disk it is by looking at the size column of the table of listed disks.

Now we select the disk:

select disk 10

This sets the disk we just specified as the target for all commands from this point forward. Now, just type the following commands, one at a time, and hit enter after each one. The format command will take a while depending on the size of your volume.

clean
This command wipes the partition or volume formatting information from the disk.

create partition primary
This command creates a primary partition.

select partition 1
This command sets the newly created partition as the target for all subsequent commands.

active
This command sets the partition as active.

format fs=fat32
This formats the partition as FAT32.

assign
This assigns the USB drive a new drive letter so you can proceed to the next step and copy files to the disk.

Now you’ve got a formatted drive with an active partition. Now we need to get the OS installation files onto the USB disk.

Type exit to leave the diskpart utility and you should be back at the normal Command Prompt.

Now, mount your installation DVD and make note of the drive letter. You should be able to use an ISO mounter to mount an image directly if you wish, but I didn’t try it.

So let’s suppose that your USB drive now has a drive letter of H:\ and your DVD or other install media has a drive letter of F:\

xcopy f:\*.* /s/e/f h:\

Change your drive letters accordingly, execute that command, and wait for the copy to finish. When it’s all said and done, you’ll have a bootable OS installation USB key, and you can join me in my quest to quit buying new optical drives for every machine in the house!