I am really struggling to figure out how to fix the boot for my Ubuntu server after running some updates recently. This is the error on boot

boot error

I can't seem to see any grub loader screen for repair, so I reattached the installation ISO to the VM, and select repair. I've tried a few options, but the result is always the same.

I can get execute a shell on the root of what I think is my installation.

Running fdisk -l /dev/sda gives:


Uname -r shows that I am on 4.13.0-21-generic, but I have newer installations in the boot directory. I don't know if that is because an upgrade has failed, or because the version running is currently from the CD ISO.

I have tried auto removing to clean, but there were a lot of errors. I thought it might be because there was no space left on the boot partition, but I believe there is plenty.

I have also tried update-initramfs on several of the kernel versions, but I get errors such as


I have tried the advice for similar looking issue here including the mount options Kernel Panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0) but still get the same error.

The disks/partitions are not encrypted. This is all being run from a Bhyve VM from FreeNAS.

The result of lsblk is: lsblk

When I am asked when booting from the original CD, what I want to connect root to, I am selecting the AtlassianServers--vg-root option. It then displays a message saying there is also a boot/efi partition which will also be mounted.

I'm a bit stuck what to try next. Is there a way to repair it that's fairly straightforward, or do I just install again over the top, and keep the underlying files mostly intact?

  • I have even now tried to re-install Ubuntu from the original ISO (keeping the data). I can now see the grub screen, but still get the kernel panic message, no matter if I try 4.13.0-37 or 38, or any of the recovery modes
    – Zief
    Apr 20, 2018 at 10:03

1 Answer 1


Have you tried updating the initramfs for the running kernel?

sudo update-initramfs -u -k $(uname -r)
sudo update-grub
  • Hi, yes, with errors. I possibly updated this as you were replying. There is a screen with errors received
    – Zief
    Apr 19, 2018 at 10:55
  • What I mean is it failed with a similar error as shown. I previously tried it for the running 4.13.0-21-generic, and it error'd too. I have since used autoremove (possibly stupidly?) and it has left only 4.13.0-37 and 4.13.0-38 versions in the boot directory, but hasn't cleanly removed version 21. Now when running initramfs on version 21 there are errors with depmod as there are missing directories. I assume it is only running version 21 because that is on the CD anyway? Perhaps I am wrong and that was the version being used, as the others failed, I'm not really sure at this stage...
    – Zief
    Apr 19, 2018 at 11:00

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