Prior to shutting down computer (Ubuntu 22.04) everything worked fine. When I came back a few days later neither LibreOffice 7.5 nor Ubuntu Software would start up.Totally mystified. Any suggestions?
The following has been added after @waltinator suggested running journalctl --since="-5 minutes". it's a portion of the output, including both before and after attempting to start "Ubuntu Software"...
Jul 19 12:20:35 tim-*** systemd[2844]: snap.snapd-desktop-integration.snapd-desktop-integration.service: Scheduled restart job, restart counter is at 1811.
Jul 19 12:20:35 tim-*** systemd[2844]: Stopped Service for snap application snapd-desktop-integration.snapd-desktop-integration.
Jul 19 12:20:35 tim-*** systemd[2844]: Started Service for snap application snapd-desktop-integration.snapd-desktop-integration.
Jul 19 12:20:35 tim-*** snapd-desktop-i[296916]: Failed to do gtk init. Waiting for a new session with desktop capabilities.
Jul 19 12:20:35 tim-*** snapd-desktop-i[296916]: Checking session /org/freedesktop/login1/session/_33...
Jul 19 12:20:35 tim-*** snapd-desktop-i[296916]: Is a desktop session! Forcing a reload.
Jul 19 12:20:35 tim-*** snapd-desktop-i[296916]: Loop exited. Forcing reload.
Jul 19 12:20:37 tim-*** systemd[2844]: Started Application launched by gnome-shell.
Jul 19 12:20:37 tim-*** systemd[2844]: Started snap.snap-store.ubuntu-software.feff5749-f19c-4c6e-987d-f9ac7307a9b2.scope.
Jul 19 12:20:37 tim-*** audit[296920]: AVC apparmor="DENIED" operation="open" class="file" profile="snap.snap-store.ubuntu-software" name="/etc/xdg/mimeapps.list" pid=296920 comm="snap-store" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0
Jul 19 12:20:37 tim-*** kernel: audit: type=1400 audit(1689787237.299:670): apparmor="DENIED" operation="open" class="file" profile="snap.snap-store.ubuntu-software" name="/etc/xdg/mimeapps.list" pid=296920 comm="snap-store" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0
Jul 19 12:20:37 tim-*** snap-store[296920]: cannot open display: :0
Jul 19 12:20:38 tim-*** systemd[2844]: snap.snapd-desktop-integration.snapd-desktop-integration.service: Scheduled restart job, restart counter is at 1812.
Jul 19 12:20:38 tim-*** systemd[2844]: Stopped Service for snap application snapd-desktop-integration.snapd-desktop-integration.
Jul 19 12:20:38 tim-*** systemd[2844]: Started Service for snap application snapd-desktop-integration.snapd-desktop-integration.
Jul 19 12:20:38 tim-*** snapd-desktop-i[297103]: Failed to do gtk init. Waiting for a new session with desktop capabilities.
Jul 19 12:20:38 tim-*** snapd-desktop-i[297103]: Checking session /org/freedesktop/login1/session/_33...
Jul 19 12:20:38 tim-*** snapd-desktop-i[297103]: Is a desktop session! Forcing a reload.
Jul 19 12:20:38 tim-*** snapd-desktop-i[297103]: Loop exited. Forcing reload.