I finally decided to install Ubuntu 12.04 LTS on my laptop; I also upgraded the internal disk to 1TB and kept (untouched) the old 500 GB disk in a SATA-USB enclosure for sake of security (you may never know...).

Now, I need to boot again the old disk from the USB. When I choose to boot from the USB disk, Ubuntu 10.04 splash screen is displayed; after few seconds I get the following error message:

ALERT! /dev/disk/by-uuid/affc8cb...... does not exist. Dropping to a shell!

BusyBox v.1.13.3 (Ubuntu 1:1.13.3-1ubuntu11) built-in shell (ash)
Enter 'help' for a list of built-it commands.


I'm not very skilled with this stuff. How do I get Ubuntu 10.04 to start from the USB disk?

Thank you.



Two ways: Easy way is to run 12.04, then run

sudo update-grub

You should now have the option to boot the usb from the grub menu.

Other way -- fix the grub.cfg file on the usb disk. You can mount the usb onto the 12.04 system, and edit the file /mnt/sdb?/boot/grub/grub.cfg and change all the hd0 occurrences to hd1. Then try boot the usb. If successful, you can run update-grub as above and get the 12.04 system added to the usb grub menu. The uuids on the usb will not have changed,so should still be good. Any explicit /dev/sda? devices you find should also be changed to /dev/sdb?, but there really should not be any of those if uuids are used.

  • Unfortunately, neither of the proposed solutions worked. The sudo update-grub command has resulted in a new grub menu from which I can choose to boot Ubuntu 10.04; it does not help me since I was able to boot it already from the BIOS boot menu (F12 on my notebook). The above error persists... – user59114 Nov 16 '13 at 14:47

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