I have this same bug in Kubuntu 20.04. I have performed a fresh install of Kubuntu 20.04 over the Kubuntu 18.04 installed in my laptop. I formatted the root (/) and swap partitions, but kept the data in /home. Everything is working fine with the exception of the akonadi server which, in practice, renders unusable all of the KDE apps that depend on personal information management (knotes, kaddressbook, kmail...). And I think that this is a **huge** bug which should be solved as soon as possible. I have followed the instructions given in the bug description and they didn't work. As root: # sed 's|mysqld_akonadi|/usr/sbin/mysqld|' -i /etc/apparmor.d/mysqld_akonadi # diff /root/mysqld_akonadi.ORIGINAL mysqld_akonadi 5c5 < profile mysqld_akonadi { --- > profile /usr/sbin/mysqld { # systemctl reload apparmor.service As normal user: $ akonadictl start Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString) org.kde.pim.akonadiserver: Starting up the Akonadi Server... org.kde.pim.akonadiserver: Failed to connect to database! org.kde.pim.akonadiserver: Database error: "Can't connect to local MySQL server through socket '/run/user/1114/akonadi/mysql.socket' (2) QMYSQL: Unable to connect" mysqladmin: connect to server at 'localhost' failed error: 'Can't connect to local MySQL server through socket '/run/user/1114/akonadi/mysql.socket' (2)' Check that mysqld is running and that the socket: '/run/user/1114/akonadi/mysql.socket' exists! org.kde.pim.akonadiserver: Failed to remove runtime connection config file org.kde.pim.akonadiserver: Shutting down AkonadiServer... org.kde.pim.akonadicontrol: Application '/usr/bin/akonadiserver' exited normally... There is nothing suspicious in /var/log/mysql/error.log (in fact, it is empty). The worst thing is this: # ps aux | grep mysql mysql 1231 0.2 1.8 2070104 297892 ? Ssl ago15 14:06 /usr/sbin/mysqld # service mysql stop # service mysql start Job for mysql.service failed because the control process exited with error code. See "systemctl status mysql.service" and "journalctl -xe" for details. root@hermes:/etc/apparmor.d# ps aux | grep mysql root 161552 0.0 0.0 11532 740 pts/5 S+ 20:00 0:00 grep --color=auto mysql # systemctl status mysql.service ● mysql.service - MySQL Community Server Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled) Active: failed (Result: exit-code) since Tue 2020-08-18 20:00:27 CEST; 51s ago Process: 161540 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=0/SUCCESS) Process: 161548 ExecStart=/usr/sbin/mysqld (code=exited, status=1/FAILURE) Main PID: 161548 (code=exited, status=1/FAILURE) ago 18 20:00:27 hermes systemd[1]: mysql.service: Scheduled restart job, restart counter is at 5. ago 18 20:00:27 hermes systemd[1]: Stopped MySQL Community Server. ago 18 20:00:27 hermes systemd[1]: mysql.service: Start request repeated too quickly. ago 18 20:00:27 hermes systemd[1]: mysql.service: Failed with result 'exit-code'. ago 18 20:00:27 hermes systemd[1]: Failed to start MySQL Community Server. Once the original mysqld_akonadi file is restored I can start the mySQL server again: # cp /root/mysqld_akonadi.ORIGINAL mysqld_akonadi # systemctl reload apparmor.service # service mysql start # ps aux | grep mysql mysql 162098 8.1 2.1 2135372 357764 ? Ssl 20:04 0:00 /usr/sbin/mysqld root 162155 0.0 0.0 11532 736 pts/5 S+ 20:04 0:00 grep --color=auto mysql # systemctl status mysql.service ● mysql.service - MySQL Community Server Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled) Active: active (running) since Tue 2020-08-18 20:04:39 CEST; 15s ago Process: 162074 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=0/SUCCESS) Main PID: 162098 (mysqld) Status: "Server is operational" Tasks: 39 (limit: 18989) Memory: 355.5M CGroup: /system.slice/mysql.service └─162098 /usr/sbin/mysqld ago 18 20:04:38 hermes systemd[1]: Starting MySQL Community Server... ago 18 20:04:39 hermes systemd[1]: Started MySQL Community Server. Current versions of packages (Kubuntu 20.04 is up to date): # lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 20.04.1 LTS Release: 20.04 Codename: focal # dpkg -l apparmor* Deseado=desconocido(U)/Instalar/eliminaR/Purgar/retener(H) | Estado=No/Inst/ficheros-Conf/desempaqUetado/medio-conF/medio-inst(H)/espera-disparo(W)/pendienTe-disparo |/ Err?=(ninguno)/requiere-Reinst (Estado,Err: mayúsc.=malo) ||/ Nombre Versión Arquitectura Descripción +++-=======================-=================-============-======================================== ii apparmor 2.13.3-7ubuntu5.1 amd64 user-space parser utility for AppArmor un apparmor-profiles-extra (no hay ninguna descripción disponible) ii apparmor-utils 2.13.3-7ubuntu5.1 amd64 utilities for controlling AppArmor # dpkg -l akonadi* Deseado=desconocido(U)/Instalar/eliminaR/Purgar/retener(H) | Estado=No/Inst/ficheros-Conf/desempaqUetado/medio-conF/medio-inst(H)/espera-disparo(W)/pendienTe-disparo |/ Err?=(ninguno)/requiere-Reinst (Estado,Err: mayúsc.=malo) ||/ Nombre Versión Arquitectura Descripción +++-==========================-==================-============-============================================ ii akonadi-backend-mysql 4:19.12.3-0ubuntu2 all MySQL storage backend for Akonadi un akonadi-backend-postgresql (no hay ninguna descripción disponible) un akonadi-backend-sqlite (no hay ninguna descripción disponible) un akonadi-kde (no hay ninguna descripción disponible) ii akonadi-server 4:19.12.3-0ubuntu2 amd64 Akonadi PIM storage service ii akonadiconsole 4:19.12.3-0ubuntu1 amd64 management and debugging console for akonadi # dpkg -l mysql* Deseado=desconocido(U)/Instalar/eliminaR/Purgar/retener(H) | Estado=No/Inst/ficheros-Conf/desempaqUetado/medio-conF/medio-inst(H)/espera-disparo(W)/pendienTe-disparo |/ Err?=(ninguno)/requiere-Reinst (Estado,Err: mayúsc.=malo) ||/ Nombre Versión Arquitectura Descripción +++-=====================-=======================-============-==============================================================> ii mysql-client 8.0.21-0ubuntu0.20.04.4 all MySQL database client (metapackage depending on the latest ver> un mysql-client-5.7 (no hay ninguna descripción disponible) ii mysql-client-8.0 8.0.21-0ubuntu0.20.04.4 amd64 MySQL database client binaries un mysql-client-core-5.7 (no hay ninguna descripción disponible) ii mysql-client-core-8.0 8.0.21-0ubuntu0.20.04.4 amd64 MySQL database core client binaries ii mysql-common 5.8+1.0.5ubuntu2 all MySQL database common files, e.g. /etc/mysql/my.cnf un mysql-common-5.6 (no hay ninguna descripción disponible) ii mysql-server 8.0.21-0ubuntu0.20.04.4 all MySQL database server (metapackage depending on the latest ver> un mysql-server-5.5 (no hay ninguna descripción disponible) un mysql-server-5.7 (no hay ninguna descripción disponible) ii mysql-server-8.0 8.0.21-0ubuntu0.20.04.4 amd64 MySQL database server binaries and system database setup un mysql-server-core-5.7 (no hay ninguna descripción disponible) ii mysql-server-core-8.0 8.0.21-0ubuntu0.20.04.4 amd64 MySQL database server binaries I have also tried to disable mysql in apparmor through aa-disable (and restarting apparmor after that) but nothing has worked so far. I would be very grateful if someone could shed some light regarding this problem. As I said, so far I have been unable of working with KDE's personal apps (knotes, etc.). Searching information, I have read in Inet that some people report that this problem is solved using mariadb instead of mysql, but this is something that I'm not planning since in my work I have to use mysql. Please, help, this situation is particularly annoying. Thanks in advance.