I have access to my dads laptop, we share it. I would like to use Ubuntu on it without affecting his machine. I dont want to dual boot since he is used to way the machine works. I have purchased an external SSD.

How can I install Ubuntu on that ssd such that when I connect the ssd to the laptop it boots in to Ubuntu and when unplugged it boots to Windows just like he is used to.


  • After installed Ubuntu into external SSD, you must setup Grub menu with command sudo update-grub. You like it or not, an extraneous GRUB entry is made into EFI partition in Windows 10. This will be reflected when you pay a visit to BIOS setup screen. i.e. you will see the presence of three bootloaders. To remove this extraneous GRUB, just follow Part-IV of my answer to the post Dual Boot Windows 10 and Linux Ubuntu on Separate SSD. Good luck! – Marmayogi Apr 4 '19 at 2:20
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    UEFI or BIOS hardware & Windows install. Newer systems are UEFI and a bit more complicated. You need to partition in advance and if UEFI be sure to have the ESP - efi system partition on your SSD for booting. But grub will default install to first drive. You then can use Boot-Repair to reinstall grub to SSD as that works, and erase Ubuntu boot from internal drive. See: askubuntu.com/questions/913716/… & help.ubuntu.com/community/UEFI – oldfred Apr 4 '19 at 2:38
  • I read your comments @oldfred. Are you sure that boot-repair tools always fixes things up? See askubuntu.com/questions/696098/…. Intead of tools like boot-repair, we can always rely upon built-in capabilities such as diskpart to do the repair work which is very safe. – Marmayogi Apr 4 '19 at 9:46
  • Boot-Repair does not always work, sometimes you have to chroot into a system to repair it. And some think it is for Windows repairs, but it is not. But for most users the gui is easier to use than posting multiple terminal commands. Plus if it does not work we can get the detail Summary report to let us see all the details and know better what to suggest. Often issue then may not be a boot issue, but something else. – oldfred Apr 4 '19 at 12:24
  • No doubt that GUI tools are easy to use as long as it works. Personally, I always prefer GUI tool such as Grub Customizer over built-in commands such as sudo update-grub, but that is a matter convenience. But one will gain insight only through in-built commands which you can't even deny @oldfred. So, I chose and relied upon diskpart command throughout which not only helped me to finish the job but also provided me valuable insight! – Marmayogi Apr 5 '19 at 19:12

It is not much different than installing on main hard disk.

  1. Connect External SSD onto your machine
  2. Connect Ubuntu installation medium onto your machine
  3. Enter BIOS, choose boot from Ubuntu installation medium
  4. In Ubuntu Installation type, choose Something else
  5. Find your external SSD on the list, look for drive other than /dev/sda. (Assuming you already had Ubuntu before)
  6. Once you found it—you can partition it, the basic Ubuntu installation contain:

    • Root partition /

    • Swap partition swap

  7. Click next --> continue.
  8. The rest steps is related to username, timezone etc.

The next time you want to boot to external SSD, just choose your SSD from BIOS boot menu. It will redirect to your external SSD, in which you can use Ubuntu from there.

  • oh interesting....it wont add the dual boot menu in this manner ? I can just unplug the drive and it will boot back to windows, no dual boot menu – ubuntububuntu Apr 4 '19 at 1:49
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    @ubuntububuntu As long as you ensure that the drive for GRUB installation is set to your external SSD, it won't affect the Windows bootloader on the internal drive. – Nonny Moose Apr 4 '19 at 1:53
  • awesome, thank you so much. I was worried I would have to disconnect the windows drive in order to do this – ubuntububuntu Apr 4 '19 at 2:09
  • Never make the mistake of meddling with drives such as plugging or unpluging! Please you follow my answer to the post Dual Boot Windows 10 and Linux Ubuntu on Separate SSD. Good luck! – Marmayogi Apr 4 '19 at 2:18

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