Snap on Kubuntu 21.10
I’ve been using Kubuntu with Snap for quite a while and no bigger issues so far.
Today all my snap apps stopped launching, reporting the following error:
/user.slice/user-1000.slice/session-3.scope is not a snap cgroup
How can I fix this?
This appears to be a recent issue and hopefully if a bug will get fixed soon.
I am running KDE on MX 21 Wildflower (in systemd mode to enable snap) and so have a similar OS as you.
I found a few references that I used to figure out the fix:
https://forum.snapcraft.io/t/cannot-launch-snap-applications-with-cgroup-v2/27700/2
https://github.com/Yubico/yubioath-desktop/issues/763
https://stackoverflow.com/questions/65977607/grub-error-systemd-unified-cgroup-hierarchy-0-not-found
==
The main fix(es) appear to be to install dbus-user-session, and to edit your /etc/default/grub file with this line: (as sudo or root)
-
try:
sudo apt install dbus-user-session
-
(first back up your
/etc/default/grubfile)
Then edit the line in /etc/default/grub as follows:
GRUB_CMDLINE_LINUX="systemd.unified_cgroup_hierarchy=1"
Then run sudo update-grub and reboot.
Hopefully this works for you and I will follow this thread to see how it goes for others.
For me, the solution was to "correct" the environment variable DBUS_SESSION_BUS_ADDRESS to this:
export DBUS_SESSION_BUS_ADDRESS="unix:path=$XDG_RUNTIME_DIR/bus"
then run your snap and check the result.