Install bootable Ubuntu on external SSD without changing Windows 10

Question

At work I have to use Ubuntu sometimes but I'd prefer to stick to Windows and don't want to have a dual boot setup. I don't really know if this is possible, that's why I am asking here before breaking my OS. I want to install Ubuntu on an external SSD Harddrive that will be connected to my computer via a USB3 port. When the SSD is plugged in I'd like the computer to directly boot into Ubuntu, whilst booting to Windows 10 when the harddrive is unplugged. In addition to that I'd like to have some space to share data between both operating systems.

I tried to search to problem online but came up only with dual boot solutions.

So is it possible to achieve what I want and can someone maybe show me a tutorial how to do it?

Solution

This is a summary of the accepted answer of the Ask Ubuntu post
How to install Ubuntu on portable external Hard Drive?

• Create the Ubuntu live installation media and use it to boot your computer and choose Try Ubuntu
• Plug in the external hard drive
• Start gparted. In most cases, the internal disk will be sda and the external sdb, but this is not guaranteed.

• Partition the external disk into one or two partitions and note their numbers:

  • If you need a swap partition, format it as linux-swap
  • The rest of the disk format as ext4

• Start the Ubuntu installer from the icon on the desktop or on the launcher. When asked how to install, choose Something Else.

• In the partition editor, highlight the ext4 partition and click Change. Follow the dialogs to:

  • Use the partition as ext4
  • Mount to /
  • Format

• Still in the editor, highlight the swap partition and click Change and choose linux-swap

• Change the installation of the bootloader to the external disk, most likely /dev/sdb. It is important not to overwrite the bootloader on the internal hard drive.

• Double-check your partition choices, then click Install Now.

• Set the USB disk as the first in the BIOS boot order.

From now on, to run Ubuntu boot the computer with the USB plugged in. The boot menu on the USB will show both Ubuntu on the external drive and Windows on the internal drive, and you may choose the one you want.

If you boot without the USB, you will boot into Windows normally.

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For another possibility using the Windows Subsystem for Linux (WSL), see the article
How-to Install WSL Distros On External Disks

Comments

[Dominik Buchner]

Unfortunatly, a virtual machine is too slow to do the stuff I need to process. However I've read stuff about the Ubuntu Boot Manager being installed on the first harddrive anyway and Windows not being able to boot any longer without the external harddrive connected. Is there a need to disconnect the Windows Harddrive before installing Ubuntu on the external harddrive?

[Genaro Morales]

No, Is like the same process when you create a live usb, you need to install the grub to the harddrive so the machine can boot from there. Did you try to create like a live usb with your drive? using rufus for example?

[Dominik Buchner]

Not yet, cause I was afraid to damage my installation. Do you know any good tutorial for that? I only installed Ubuntu on a main harddrive.

[Genaro Morales]

You can take a look howtogeek.com/howto/linux/… Please consider that if you create this the entire disk will be erased. If you don't pretend to use the entire disk I would suggest to have a usb with at least 64 G to store all you need. If you want to use the hard disk then you will need to open the Rufus, click on the interface and do CTRL+ALT+F to display the drive. Remember that Ubuntu doesn't ask for too much drive space for the operating system so could use an 8G and test the performance.