Jeff Wouters's Blog

When I tried to create a bootable installation USB stick for Windows 8 by using Microsoft’s Windows 7 USB/DVD Download Tool, I found that the procedure failed at a few percent and gave some error that the USB stick could not be used to create the installation media.
After trying the same procedure on my two other laptops, I received the same error.

• Open a command prompt.
• Type “diskpart”.
• Type “list disk” and note down the disk number of your USB drive.
• Type “select disk 1”, where “1” is to be replaced by the disk number you wrote down in the previous step.
• Type “clean”.
• Type “create partition primary”.
• Type “select partition 1”.
• Type “active”.
• Type “format fs=ntfs”.
  This may take some time, depending on the size and speed of the USB device you’re using.
• Type “assign”.
• Type “exit”.

Now, try creating the bootable installation USB stick for Windows 8 again

Big fat note: The USB device you use must be at least 4GB!