Ubuntu – Failed to get canonical path of /cow


I am trying to install Ubuntu 12.10 for quite some time, and passing hurdles one by one. Now I am in a situation as follows.

I have got a PC and 10 GB HDD which will be totally dedicated to Ubuntu so no option of Wubi and dual boot.

I was trying to install from DVD, but it is getting stuck at "Out of frequency" error. So I had to adapt for USB boot option. But my PC is USB non bootable, so workaround is "Plop Boot Manager". So I am doing the installation procedure as follows:

  1. starting from a CD drive which is having plop installed.
  2. opting for for USB boot in plop options.
  3. booting begins from USB.
  4. monitor eventually gives "out of frequency" error
  5. press Shift+Alt+F1 to get the terminal.
  6. open the grub with sudo nano /etc/default/grub.
  7. do necessary changes.
  8. sudo update-grub.

Now here I am getting error as follows:

/usr/sbin/grub-probe:error:failed to get canonical path of /cow.

My system is

P4 3.06 GHz, 1 GB ram , 10 GB HDD without an OS, monitor CRT lg StudioWorks (7 years old). Mobo Mercury P4 266a NDMx (865 equivalent). The whole system is perfectly in working condition under XP, but it is USB non bootable, and all other devices working perfectly.

What should I do next?

Best Answer

After booting from the Ubuntu live CD (tried 14.04 and 16.04) I was able to work around this problem by running update-grub chroot'ed to the grub partition. (Substitute /dev/sda1 below with whatever partition you installed grub on. All commands as root.)

mkdir /mnt/chrootdir
mount /dev/sda1 /mnt/chrootdir
for dir in proc dev sys etc bin sbin var usr lib lib64 tmp; do
    mkdir /mnt/chrootdir/$dir && mount --bind /$dir /mnt/chrootdir/$dir
chroot /mnt/chrootdir
grub-install /dev/sda # May not be required
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