I have a serious problem installing ubuntu on my external hard disk. During installation i press "something else". It says that the external HDD is /dev/sdc. I install Ubuntu and bootloader there. Everything is fine during installation. When I restart my computer to boot ubuntu it says that grub can't find the partition and shows grub rescue. If I boot from windows and use "easeus partition master", it says that the external HDD is /dev/sdb. I tried to install ubuntu in several ways but every time I failed. So I thought that the change between the /sdc and /sdb must be the problem. Can someone help me?

I am trying to install ubuntu 14.04 in a Toshiba Canvio Basics 1TB using a DVD in the following ways:

  1. Having the internal HDD disconnected

  2. Having the internal HDD disconnected and creating a 500MB /boot partition

  3. Having the internal HDD disconnected and installing bootloader on the linux partition, not the HDD

  4. Having the internal HDD connected and installing bootloader on external HDD

  5. Having the internal HDD connected and installing creating 500MB /boot partition

  6. any other combination of the above

The result is always the same: grub rescue. It says that it can't find the grub location. Through a little search on the internet I found that many people have the same problem with me.

You can install ubuntu on a flash drive but you can't on an external HDD. This is frustrating.

  • Whether a drive is called sda or sdb depends on the order the drives are recognized. It should not matter to the installation procedure. If the external drive contains an Ubuntu partition, and you installed Ubuntu there, it should be able to boot from that partition. – Jos Apr 3 '15 at 11:52
  • Could you please give us a bit more information like: what version of Ubuntu you're running? Boot from an external DVD with the external HD inserted. Go to a terminal and type gparted --list. Please edit your question and add this information... (we need more info!) ;-) – Fabby Apr 6 '15 at 19:18

Have you tried the "Boot Repair" here. That just might repair the booting problem


I did something similar a few days ago- installed Ubuntu on an "external" drive. I installed Ubuntu and the swap partition on the external drive, and the bootloader on my internal drive. Also try when formatting the external drive, I set it up as Ext4, "primary" (not logical). Not sure if any of these are your problem, but everything has been working fine for me so far. Good luck.

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