"failed to mount Mount unit for <program>" when restarting the system

Question

When I restart my Ubuntu 18.04 system, it suddenly crashes and shows a long list of [FAILED] messages as shown above, for example:

[FAILED] Failed to mount Mount unit for gtk-common-themes, revision 1198
See 'systemctl status "snap-gtk\\x2dcommon\\x2dthemes-1198.mount"' for details

and other mount errors like

[FAILED] Failed to mount FUSE Control File System

What could be the problem here, and how can I fix it?

Solution

If you deleted snap files manually, for instance, in order to clean up space, some .mount files were left in /etc/systemd/system/, like /etc/systemd/system/snap-core20-975.mount.

You can try the following command:

grep -r What /etc/systemd/system/|sed -E 's/.*What=(.*)/\1/g'|xargs ls -la {}

The output will be:

ls: cannot access '/var/lib/snapd/snaps/snap-postman_81.snap': No such file or directory
-rw------- 2 root root  64233472 Mai 19 22:11 /var/lib/snapd/snaps/****.snap
....

So, now you know what snaps are missing and can decide what to do, e.g. remove obsolete .mount files.

Comments

[Joshua Besneatte]

I welcome to ask ubuntu. If you can copy and paste the output of the error into your question and wrap it in code brackets {} that would be awesome. thanks!

[Abhirock]

Thanks@Joshua Besneatte however I am getting error in boot level I took pictures but cannot upload here it's giving me error while upload pictures in ask Ubuntu

[Rinzwind]

The error will be stored in /var/log/ (probably kern.log or syslog) Oh and regarding the image: you need the 1st error... what you show us are results from a previous problem.

[Abhirock]

thanks@ Rinzwind sorry when I restart my laptop only this error come on my screen

[Paul Benson]

Looks like you have a corrupt system. You can boot into Live Ubuntu and try running fsck to repair the system. If that doesn't work and you don't have a an image back-up of your system, you're looking at a re-install.

[alchemy]

I ended up doing apt purge snapd and it rebuilt everything after messing up moving the /var/lib/snapd to a partition. askubuntu.com/questions/1029562/…