Can I install Ubuntu on the same partition as windows 10

Question

I have a 256 ssd with 40 gB free. I don’t want to partition it. Can I install Ubuntu alongside windows 10 on the same partition? If so, is there a special way to install it?

Answer 1

Ubuntu and Windows can NOT be on the same partition. Ever.

...unless one is a Virtual Machine.

...or an image file of a system (instead of an installed system).

Answer 2

GRUB2 for Windows

This is a Persistent Live install, not a Full install

You can download the Ubuntu ISO to a folder on the Windows partition of your HDD.

You can install GRUB2 for Windows, (Grub2Win): https://sourceforge.net/projects/grub2win/files/

You can create a persistence writable file.

You can boot the Ubuntu ISO using GRUB2 for Windows.

GRUB Menuentry:

  menuentry "ubuntu-20.04.1-desktop-amd64.iso" {
     set isofile="/ubuntu-20.04.1/ubuntu-20.04.1-desktop-amd64.iso"
     loopback loop (hd0,1)$isofile
     linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=$isofile noprompt noeject maybe-ubiquity nopersistent
     initrd (loop)/casper/initrd
  }

A second method using WINGRUB can be found here: https://askubuntu.com/a/1309642/43926