I managed to solve my problem by renaming .config and .cache as explained here https://askubuntu.com/questions/831569/unity-is-broken- launcher-menu-bar-dash-disappeared-unity-reinstall-doesnt-w/831570
To sum up: (1) I did a security update on March 2nd then did a reboot on March 3rd (2) Both the launcher and menu bar disappeared in my main session (3) .Xauthority was owned by root, I do not know since when and if it caused any issue (4) .config and/or .cache were likely corrupted, I do not know if this was caused by the update ** Summary changed: - Task bar and launchpad are missing + Task bar and launchpad disappeared -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/1753233 Title: Task bar and launchpad disappeared Status in lightdm package in Ubuntu: Invalid Bug description: I am using Ubuntu 16.04.4 LTS and lightdm 1.18.3-0ubuntu1.1 After I enter my password in the login screen, both task bar and launchpad are missing. I think this problem has started after the last security update. Remark: The guest login is working fine. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: lightdm 1.18.3-0ubuntu1.1 ProcVersionSignature: Ubuntu 4.4.0-112.135-generic 4.4.98 Uname: Linux 4.4.0-112-generic x86_64 ApportVersion: 2.20.1-0ubuntu2.15 Architecture: amd64 Date: Sun Mar 4 12:12:23 2018 ProcEnviron: TERM=linux PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=fr_FR.UTF-8 SHELL=/bin/bash SourcePackage: lightdm UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1753233/+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
