Ubuntu stopped booting forces GRUB selection

I have been running Ubuntu 18.04 as a HTPC and autostarting Kodi.

It now hangs and stops at GRUB wanting a selection, and going to emergency mode.

As it tries to boot it gives the following errors:

Warning: Failed to connect to lvmetad. Falling back to device mapping.
/dev/mapper/KodiBuntu--vg-root: clean, {I clipped files/blocks info}
[Time] Timed out waiting for device dev-disk-by\x2duuid-8ef078aa\x2db90a\x2d451e\x2d91dc\x2d4ffcc4208e26.device.
[Depend] Dependency failed for File System Check on /dev/disk/by-uuid/8ef078aa-b90a-451e-91dc-4ffcc4208e26.
[Depend] Dependency failed for /boot.
[Depend] Dependency failed for Local File Systems.
[Time] Timed out waiting for device dev-mapper-KodiBuntu\x2d\x2dvg\x2dswap_1.device.
[Depend] Dependency failed for /dev/mapper/KodiBuntu--vg-swap_1.device.
[Depend] Dependency failed for Swap

What should be my first step to getting this straightened out? TIA.

First step ? - get a new hard disk ready.

Ignore the lvmetad warning, but the rest look like you're not talking to the disk properly. How many disks, how are they configured ?.
Might try reseating/cleaning everything and hope for the best. Note my sigline.

Originally Posted by syg00 First step ? - get a new hard disk ready. Ignore the lvmetad warning, but the rest look like you're not talking to the disk properly. How many disks, how are they configured ?. Might try reseating/cleaning everything and hope for the best. Note my sigline.

Single disk. Connections look fine.

so it has been working well? for how long, how many reboots has it been ok?

Originally Posted by rkmorgan [Time] Timed out waiting for device dev-disk-by\x2duuid-8ef078aa\x2db90a\x2d451e\x2d91dc\x2d4ffcc4208e26.device.

clearly this is the issue.
either you or the system did "something" that caused this - then try to find out what.
i think i remember having to boot some live distro, and adjust the UUIDs in /etc/fstab.
if you or the system really did "nothing", means the hard drive has changed somehow?

Fire up a liveCD and run smartctl on the disk would be a reasonable start. At least you'll be able to see the logs if even that won't run.

Originally Posted by ondoho so it has been working well? for how long, how many reboots has it been ok? clearly this is the issue. either you or the system did "something" that caused this - then try to find out what. i think i remember having to boot some live distro, and adjust the UUIDs in /etc/fstab. if you or the system really did "nothing", means the hard drive has changed somehow?

I have a couple possibilities in mind as to what happened. The most likely being an improper shutdown.

Originally Posted by syg00 Fire up a liveCD and run smartctl on the disk would be a reasonable start. At least you'll be able to see the logs if even that won't run.

According to smartctl, the disk is healthy.

Originally Posted by rkmorgan [Time] Timed out waiting for device dev-disk-by\x2duuid-8ef078aa\x2db90a\x2d451e\x2d91dc\x2d4ffcc4208e26.device.

If I may toss out a few suggestions: blkid to confirm UUIDs on your disk. dmesg to check for driver messages. pvs, vgs, lvs and pvscan to look into LVM. udevadm info --path=/dev/sdX (or was it /sys/block/sdX?) to get udev's opinion. What happens if you access that disk, e.g. dd if=/dev/disk/by-uuid/<UUID> or dd if=/dev/sdX?

I wonder if the /dev/disk link is just missing for some reason, like udev having a cold, and otherwise everything is fine.

Originally Posted by rkmorgan It now hangs and stops at GRUB wanting a selection, and going to emergency mode.

I understand this as "Grub displays the menu but doesn't boot automatically". If that is the case, it seems Grub has lost its default menuentry. At the emergency prompt, I would ensure /boot is mounted, check /etc/default/grub and re-run grub-mkconfig.

Originally Posted by berndbausch If I may toss out a few suggestions: blkid to confirm UUIDs on your disk. dmesg to check for driver messages. pvs, vgs, lvs and pvscan to look into LVM. udevadm info --path=/dev/sdX (or was it /sys/block/sdX?) to get udev's opinion. What happens if you access that disk, e.g. dd if=/dev/disk/by-uuid/<UUID> or dd if=/dev/sdX? I wonder if the /dev/disk link is just missing for some reason, like udev having a cold, and otherwise everything is fine.

Booting from a LiveCD gives the following values.


According to Gparted sda is configured as:
/dev/sda1 - ext2 - blank mount point - boot
/dev/sda2 - extended - blank mount point - blank flag
/dev/sda5 - lvm2 pv - KodiBuntu-vg - lvm

blkid is showing:
/dev/sda1: UUID="8ef078aa-b90a-451e-91dc-4ffcc4208e26" TYPE="ext2" PARTUUID="af8c41ca-01"
/dev/sda5: UUID="xPpdOR-RD0W-trBy-rfdn-nvGx-f88X-VOFMWy" TYPE="LVM2_member" PARTUUID="af8c41ca-05"
/dev/mapper/KodiBuntu--vg-root: UUID="7b63270b-1486-41f2-96a0-ed7446dbbab3" TYPE="ext4"
/dev/mapper/KodiBuntu--vg-swap_1: UUID="cbbae2f0-eabe-4ea2-abf8-47ba21132ac6" TYPE="swap"

Interesting.....

When it gets to the GRUB selection menu, I select:
Advanced options for ubuntu

Then I am presented with other options, and I select this:
Ubuntu with linux 4.15.0-34 generic (recovery mode)

Once the menu comes up with recovery options, I select this:
grub - update grub boot loader

It gives me this message:
Continuing will remount your / filesystem in read/write mode and mount any other filesystem defined in /etc/fstab.
Do you wish to continue?

I allow it by selecting:
Yes

After it goes through its process, it goes back to the recovery menu. Then I select this:
Resume - resume normal boot

At this point the system loads as it should. It loads up directly into KODI as it previously has and is completely functional as it should be.

If I restart, the GRUB menu still appears. If I select the option to load Ubuntu, it fails with the same messages as I originally posted.

When booting it is supposed to load directly into KODI.