Ubuntu 16 not booting

Question

I've been using Ubuntu 16 and yesterday it was taking too much time to boot. So I forced restart it by pressing and holding the power button. Later when I tried to boot it,it's "Unable to mount root fs on unknown-block(0,0) How can I fix this without losing my data?

Yes i'am able to. I can see 4 options : 1.Ubuntu 2.Advanced options for Ubuntu 3.Memory Test (memtest+86+) 4.Memory Test (memtest+86+, serial console 115200) — Himanshu Gupta, Nov 26 '17 at 16:53
second kernel is Ubuntu, with Linux 4.4.0-101-generic (upstart) . — Himanshu Gupta, Nov 26 '17 at 17:03
Try the one that says recovery mode. But forcing shutdown can cause other issues where you need fsck to get back to original issue. Never force shutdown, use REISUB. https://askubuntu.com/questions/926461/whats-the-difference-between-the-magic-reisub-reset-and-holding-down-the-power — oldfred, Nov 26 '17 at 17:06
@Videonauth how do i make sure, which is correct kernel version? — Himanshu Gupta, Nov 26 '17 at 17:20
I selected both upstart and recovery mode,in both cases it is redirecting me to the same situation i showed in the pic above. — Himanshu Gupta, Nov 26 '17 at 17:28

score 1 · Answer 1 · answered Nov 26 '17 at 18:38

Start with a live USB/CD, choose 'Try Ubuntu' and open a terminal (Ctrl+Alt+T):

List your partitions with sudo fdisk -l and choose the right one to mount:
```
sudo mount /dev/sdaX /mnt
```
Where sdX is your Ubuntu installation on your HDD. If you have an EFI boot system you need to mount your EFI partition as well.
```
sudo mount /dev/sdY /mnt/boot/efi
```
Where sdY is your EFI partition.

Now mount the following and chroot into your install

# in case you need to reinstall the kernel (you will need LAN connection for this)
sudo cp /mnt/etc/hosts /mnt/etc/hosts.old
sudo cp /etc/hosts /mnt/etc/hosts
sudo cp /etc/resolv.conf /mnt/etc/resolv.conf

# the below is always needed
sudo mount -o bind /dev /mnt/dev
sudo mount -o bind /dev/pts /mnt/dev/pts
sudo mount -t sysfs /sys /mnt/sys
sudo mount -t proc /proc /mnt/proc
sudo chroot /mnt

Create a update-initramfs and update-grub. Make sure you put the right version number into the next line, you can find this by dpkg --list | grep linux-image.
```
update-initramfs -u -k 4.4.0-101-generic
update-grub
```
If that step fails for whatever reason you might want to reinstall that kernel with:
```
 apt install --reinstall linux-image-4.4.0-101-generic linux-image-extra-4.4.0-101-generic linux-firmware
```

Unmount and reboot your system.

exit
sudo umount /mnt/dev/pts
sudo umount /dev /mnt/dev
sudo umount /mnt/sys
sudo umount /mnt/proc
sudo umount /mnt/boot/efi
sudo umount /mnt
reboot

Ubuntu 16 not booting

1 Answers1