This problem is triggered by incorrect "/var/lib/snapd/seed/seed.yaml" files. At various points during the development cycles they were incorrect and that has (almost) no effect on the live-cd or the installed system. However on the next snapd refresh it would trigger the hang people are experiencing. The hang is caused by services waiting for "snapd" to finish seeding but that never happens because the seed.yaml is incorrect.
The best workaround is to $ sudo mv /var/lib/snapd/seed/seed.yaml /var/lib/snapd/seed/seed.yaml .disabled and re-run the upgrade. Versions of snapd from ~April 2020 will do this automatically for you if they detect a broken seed. So I will close this bug as fixed because there is an automatic workaround in snapd now. The tooling around the livecd got also improved AIUI so that incorrect seed.yaml should be much harder to create now. ** Changed in: snapd Status: Confirmed => Fix Released ** Changed in: snapd (Ubuntu) Status: Confirmed => Fix Released -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1776622 Title: snapd updates on focal never finish installing. Can't install any other updates. Status in snapd: Fix Released Status in snapd package in Ubuntu: Fix Released Status in systemd package in Ubuntu: Invalid Bug description: snapd (2.33+18.10ubuntu3) cosmic never finishes installing. Can't install any other updates. The first time I gave up waiting and killed it. Then... $ sudo apt full-upgrade E: dpkg was interrupted, you must manually run 'sudo dpkg --configure -a' to correct the problem. $ sudo dpkg --configure -a Setting up snapd (2.33+18.10ubuntu3) ... snapd.snap-repair.service is a disabled or a static unit, not starting it. << never ends >> All the while the snap and snapd process use about 0.3% CPU (which is more than usual). WORKAROUND: sudo killall apt dpkg sudo dpkg -r snapd gnome-software-plugin-snap sudo apt update sudo apt full-upgrade To manage notifications about this bug go to: https://bugs.launchpad.net/snapd/+bug/1776622/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp