So I want to make a dual boot installation with Windows 10 and Ubuntu. In order to do that, I need to install Windows 10 first. The problem is that when I create an installation USB with a Windows 10 image (taken from here) and try to boot from it, I get the following error:

error: unknown filesystem
Entering rescue mode...
grub rescue>

I tried creating an installation USB using dd if=/path/to/windows/installer/image.iso of=/dev/sdd. I also tried woeusb utility.

The questions are:

  1. How do I properly create a Windows 10 USB installer and boot from it, provided that I don't have access to a Windows machine?
  2. Why do I even get a message from grub? My current understanding is that when you boot from an USB, then whatever bootloader that is on the USB should be used.

1 Answer 1


First, you need to make a partition on your USB and format it in an appropriate filesystem, for Windows NTFS would work. Probably it's a good idea to use parted for creating the disk label anew (msdos or gpt)

Install the tool for working with NTFS and format the newly created partition:

sudo apt-get install ntfs-3g
sudo mkfs.ntfs /dev/sdXX -o 

You can't use dd for writing Windows on USB because it's ISO is not isohybrid. So the only option that I'm aware of is using woeusb


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