I am seeing this exact same problem. Performed a fresh install of 18.04 LTS and have remained updated the whole time. Still seeing problems with gnome-shell filling the logs. This seems to happen when the user session in gnome goes to the lock screen and you can see it go black momentarily, then recover.
Log examples: Sep 18 14:29:08 machine org.gnome.Shell.desktop[2266]: #5 0x7fff48999630 I resource:///org/gnome/gjs/modules/_legacy.js:82 (0x7f48b80b5de0 @ 71) Sep 18 14:29:08 machine org.gnome.Shell.desktop[2266]: #6 0x7fff489996f0 b self-hosted:916 (0x7f48b80f12b8 @ 367) Sep 18 14:29:08 machine gnome-shell[2266]: Object St.BoxLayout (0x5587958dee60), has been already finalized. Impossible to set any property to it. Sep 18 14:29:08 machine gnome-shell[2266]: Object St.Icon (0x558793ecab90), has been already finalized. Impossible to set any property to it. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1792702 Title: gnome-shell filling /var/log/syslog with "Object St.Icon|BoxLayout (...), has been already finalized. Impossible to set any property to it." Status in gnome-shell package in Ubuntu: Incomplete Bug description: My Ubuntu 18.04 installation is killing my disk space. It is filling /var/log/syslog with about 5gb of messages per day. I did a tail on it: PS: already upgraded to the latest packages lsb_release -rd Description: Ubuntu 18.04.1 LTS Release: 18.04 apt-cache policy gnome-shell gnome-shell: Installed: 3.28.3-0ubuntu0.18.04.2 Candidate: 3.28.3-0ubuntu0.18.04.2 Version table: *** 3.28.3-0ubuntu0.18.04.2 500 500 http://br.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages 100 /var/lib/dpkg/status 3.28.1-0ubuntu2 500 500 http://br.archive.ubuntu.com/ubuntu bionic/main amd64 Packages tail of /var/log/syslog: Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493ee54c50), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493e3717c0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493e00d150), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493e2f7ef0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493f4a1ac0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493e428090), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493e466470), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493e401fc0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493e2086c0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493e2a8dc0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493f9d8e00), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493e349860), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493e1f57f0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493e3d5e90), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493e417050), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493fa7f490), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493fa81550), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493fbf3370), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493f8f8640), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493ed5fc90), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493e264330), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493fcab090), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493e2e9830), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493fce7880), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493fcf4190), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493ffa3890), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493f955050), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493ffe2670), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x5649400a7fd0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493f34dca0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493e68b460), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493fff65e0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493fc80720), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56494010de10), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493fc11570), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x5649400a39c0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493f1de550), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x5649401b8760), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x5649400b1b60), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56494002cca0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493febc8d0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493ef1dda0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x564940105480), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x5649401606a0), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56494031e120), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.Icon (0x56493fb59a70), has been already finalized. Impossible to set any property to it. Sep 15 10:07:52 marte gnome-shell[1104]: Object St.BoxLayout (0x56493fecbc90), has been already finalized. Impossible to set any property to it. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1792702/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp