Bonjour,
Je suis parti d'un live CD Ubuntu 16.04 LTS pour l'installation de Kubuntu.
Mise à jour successive de 16.04 à 18.04 à 20.04 LTS
Le démarrage de kUBUNTU est vraiment lent surtout de l'allumage de l'ordi au panneau d'identification entre 1mn et 2mn.
Kubuntu ouvert, le fonctionnement est normal .
Est ce que la succession e mise à jour peut avoir induit quelques erreurs?
Bonjour,

Fournis les noyaux présents : 
echo; dpkg -l | awk '!/^rc/ && / linux-(c|g|h|i|lo|m|si|t)/{print $1,$2,$3,$4 | "sort -k3V | column -t"}' ; echo -e "\nNoyau courant : $(uname -mr)"
et : 
dpkg -l | grep -v ^ii
lhommegermelebien@lhommegermelebien-MS-7C02:~$ echo; dpkg -l | awk '!/^rc/ && / linux-(c|g|h|i|lo|m|si|t)/{print $1,$2,$3,$4 | "sort -k3V | column -t"}' ; echo -e "\nNoyau courant : $(uname -mr)"

ii  linux-headers-5.4.0-51                5.4.0-51.56  all
ii  linux-headers-5.4.0-51-generic        5.4.0-51.56  amd64
ii  linux-image-5.4.0-51-generic          5.4.0-51.56  amd64
ii  linux-modules-5.4.0-51-generic        5.4.0-51.56  amd64
ii  linux-modules-extra-5.4.0-51-generic  5.4.0-51.56  amd64
ii  linux-headers-5.4.0-60                5.4.0-60.67  all
ii  linux-headers-5.4.0-60-generic        5.4.0-60.67  amd64
ii  linux-image-5.4.0-60-generic          5.4.0-60.67  amd64
ii  linux-modules-5.4.0-60-generic        5.4.0-60.67  amd64
ii  linux-modules-extra-5.4.0-60-generic  5.4.0-60.67  amd64
ii  linux-headers-5.4.0-62                5.4.0-62.70  all
ii  linux-headers-5.4.0-62-generic        5.4.0-62.70  amd64
ii  linux-image-5.4.0-62-generic          5.4.0-62.70  amd64
ii  linux-modules-5.4.0-62-generic        5.4.0-62.70  amd64
ii  linux-modules-extra-5.4.0-62-generic  5.4.0-62.70  amd64
ii  linux-generic                         5.4.0.62.65  amd64
ii  linux-headers-generic                 5.4.0.62.65  amd64
ii  linux-image-generic                   5.4.0.62.65  amd64

Noyau courant : 5.4.0-62-generic x86_64
lhommegermelebien@lhommegermelebien-MS-7C02:~$ dpkg -l | grep -v ^ii
Souhait=inconnU/Installé/suppRimé/Purgé/H=à garder
| État=Non/Installé/fichier-Config/dépaqUeté/échec-conFig/H=semi-installé/W=attend-traitement-déclenchements
|/ Err?=(aucune)/besoin Réinstallation (État,Err: majuscule=mauvais)
||/ Nom                                           Version                                             Architecture Description
+++-=============================================-===================================================-============-======================================================================================================
rc  amarok                                        2:2.9.81+git202012230127-0+yasi1~7~ubuntu20.04.1    amd64        easy to use media player based on the KDE Platform
rc  blueman                                       2.1.2-1ubuntu0.2                                    amd64        Graphical bluetooth manager
rc  cinnamon-common                               4.4.8-4                                             all          Innovative and comfortable desktop (Common data files)
rc  dragonplayer                                  4:19.12.3-0ubuntu1                                  amd64        simple video player
rc  gir1.2-nemo-3.0                               4.4.2-2                                             amd64        libraries for nemo components - gir bindings
rc  gnome-accessibility-themes                    3.28-1ubuntu1                                       all          High Contrast GTK+ 2 theme and icons
rc  ibverbs-providers:amd64                       28.0-1ubuntu1                                       amd64        User space provider drivers for libibverbs
rc  kdepim-addons                                 19.12.3-0ubuntu1                                    amd64        Addons for KDE PIM applications
rc  kdepim-themeeditors                           4:19.12.3-0ubuntu1                                  amd64        Theme Editors for KDE PIM applications
rc  kmail                                         4:19.12.3-0ubuntu1                                  amd64        full featured graphical email client
rc  knotes                                        4:19.12.3-0ubuntu1                                  amd64        sticky notes application
rc  kpat                                          4:19.12.3-0ubuntu1                                  amd64        solitaire card games
rc  ksudoku                                       4:19.12.3-0ubuntu1                                  amd64        Sudoku puzzle game and solver
rc  libjs-jquery-ui                               1.12.1+dfsg-5                                       all          JavaScript UI library for dynamic web applications
rc  libkf5kmahjongglib-data                       4:19.12.3-0ubuntu1                                  all          shared library for kmahjongg and kshisen
rc  libkf5mailcommon-plugins:amd64                4:19.12.3-0ubuntu1                                  amd64        KDE PIM email utility library, plugins
rc  libkpimitinerary-data                         19.12.3-0ubuntu1                                    all          library for Travel Reservation information - arch independent data
rc  libkpimpkpass5:amd64                          19.12.3-0ubuntu1                                    amd64        library for Apple Wallet Pass reader
rc  libopenmpi-dev:amd64                          4.0.3-0ubuntu1                                      amd64        high performance message passing library -- header files
rc  libpsm-infinipath1                            3.3+20.604758e7-6                                   amd64        PSM Messaging library for Intel Truescale adapters
rc  libspnav0                                     0.2.3-1                                             amd64        Library to access 3D-input-devices (development files)
rc  linux-image-5.4.0-48-generic                  5.4.0-48.52                                         amd64        Signed kernel image generic
rc  linux-image-5.4.0-52-generic                  5.4.0-52.57                                         amd64        Signed kernel image generic
rc  linux-image-5.4.0-53-generic                  5.4.0-53.59                                         amd64        Signed kernel image generic
rc  linux-image-5.4.0-54-generic                  5.4.0-54.60                                         amd64        Signed kernel image generic
rc  linux-image-5.4.0-56-generic                  5.4.0-56.62                                         amd64        Signed kernel image generic
rc  linux-image-5.4.0-58-generic                  5.4.0-58.64                                         amd64        Signed kernel image generic
rc  linux-image-5.4.0-59-generic                  5.4.0-59.65                                         amd64        Signed kernel image generic
rc  linux-modules-5.4.0-48-generic                5.4.0-48.52                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  linux-modules-5.4.0-52-generic                5.4.0-52.57                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  linux-modules-5.4.0-53-generic                5.4.0-53.59                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  linux-modules-5.4.0-54-generic                5.4.0-54.60                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  linux-modules-5.4.0-56-generic                5.4.0-56.62                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  linux-modules-5.4.0-58-generic                5.4.0-58.64                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  linux-modules-5.4.0-59-generic                5.4.0-59.65                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  linux-modules-extra-5.4.0-48-generic          5.4.0-48.52                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  linux-modules-extra-5.4.0-52-generic          5.4.0-52.57                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  linux-modules-extra-5.4.0-53-generic          5.4.0-53.59                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  linux-modules-extra-5.4.0-54-generic          5.4.0-54.60                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  linux-modules-extra-5.4.0-56-generic          5.4.0-56.62                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  linux-modules-extra-5.4.0-58-generic          5.4.0-58.64                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  linux-modules-extra-5.4.0-59-generic          5.4.0-59.65                                         amd64        Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
rc  metacity-common                               1:3.36.1-1                                          all          shared files for the Metacity window manager
rc  odbcinst                                      2.3.6-0.1build1                                     amd64        Helper program for accessing odbc ini files
rc  openmpi-bin                                   4.0.3-0ubuntu1                                      amd64        high performance message passing library -- binaries
rc  pim-data-exporter                             4:19.12.3-0ubuntu1                                  amd64        back up and archive PIM data
rc  pim-sieve-editor                              4:19.12.3-0ubuntu1                                  amd64        IMAP Sieve filter editor
rc  python-matplotlib-data                        3.1.2-1ubuntu4                                      all          Python based plotting system (data package)
lhommegermelebien@lhommegermelebien-MS-7C02:~$
Pour nettoyer :
Le 11/02/2017, moko138 a écritPour supprimer tous ces fichiers de configuration devenus sans objets et marqués "rc", et uniquement ces fichiers, exécute : 
dpkg -l | awk '/^rc/{print $2}' | xargs -r sudo dpkg -P

sudo apt clean
Fournis : 
systemd-analyze time

systemd-analyze blame
systemd-analyze critical-chain

ls -l /var/crash

lhommegermelebien@lhommegermelebien-MS-7C02:~$ systemd-analyze time
Startup finished in 2.634s (kernel) + 26.572s (userspace) = 29.206s 
graphical.target reached after 7.521s in userspace
lhommegermelebien@lhommegermelebien-MS-7C02:~$ systemd-analyze blame
21.781s upower.service                                                                           
 5.498s apt-daily.service                                                                        
 3.402s NetworkManager-wait-online.service                                                       
 2.505s fwupd-refresh.service                                                                    
 2.473s apt-daily-upgrade.service                                                                
 2.197s dev-sda1.device                                                                          
 1.513s systemd-journal-flush.service                                                            
 1.192s snapd.service                                                                            
 1.131s mysql.service                                                                            
  701ms fwupd.service                                                                            
  690ms dev-loop0.device                                                                         
  684ms apache2.service                                                                          
  617ms dev-loop3.device                                                                         
  605ms dev-loop8.device                                                                         
  601ms dev-loop1.device                                                                         
  566ms dev-loop2.device                                                                         
  547ms dev-loop4.device                                                                         
  500ms dev-loop6.device                                                                         
  494ms tor@default.service                                                                      
  462ms dev-loop7.device                                                                         
  407ms udisks2.service                                                                          
  396ms dev-loop5.device                                                                         
  385ms accounts-daemon.service                                                                  
  380ms systemd-udevd.service                                                                    
  360ms systemd-logind.service                                                                   
  330ms networkd-dispatcher.service                                                              
  317ms snap-core-10583.mount                                                                    
  313ms snap-core18-1944.mount                                                                   
  283ms avahi-daemon.service                                                                     
  276ms NetworkManager.service                                                                   
  268ms polkit.service                                                                           
  265ms snap-gtk2\x2dcommon\x2dthemes-13.mount                                                   
  262ms snap-snapd-10492.mount                                                                   
  260ms systemd-tmpfiles-setup.service                                                           
  237ms thermald.service                                                                         
  236ms wpa_supplicant.service                                                                   
  219ms networking.service                                                                       
  197ms snap-snapd-10707.mount                                                                   
  178ms snapd.apparmor.service                                                                   
  167ms snap-gtk\x2dcommon\x2dthemes-1506.mount                                                  
  167ms snap-gtk\x2dcommon\x2dthemes-1514.mount                                                  
  149ms virtualbox.service                                                                       
  146ms systemd-resolved.service                                                                 
  146ms snap-core18-1932.mount                                                                   
  121ms systemd-rfkill.service                                                                   
  114ms ModemManager.service                                                                     
  104ms gpu-manager.service                                                                      
   98ms lm-sensors.service                                                                       
   97ms systemd-journald.service                                                                 
   96ms phpsessionclean.service                                                                  
   90ms rsyslog.service                                                                          
   85ms snap-core-10577.mount                                                                    
   84ms e2scrub_reap.service                                                                     
   84ms apport.service                                                                           
   84ms colord.service                                                                           
   83ms systemd-udev-trigger.service                                                             
   81ms teamviewerd.service                                                                      
   78ms apparmor.service                                                                         
   74ms systemd-timesyncd.service                                                                
   73ms grub-common.service                                                                      
   71ms user@1000.service                                                                        
   68ms alsa-restore.service                                                                     
   67ms keyboard-setup.service                                                                   
   56ms grub-initrd-fallback.service                                                             
   49ms dev-disk-by\x2duuid-afb66f97\x2d9f6c\x2d4cf2\x2db155\x2df0d114b10e5b.swap                
   46ms systemd-fsck@dev-disk-by\x2duuid-f4fd94ab\x2dee32\x2d4af2\x2da59d\x2d5ff8166bb05a.service
   46ms systemd-modules-load.service                                                             
   39ms systemd-sysusers.service                                                                 
   38ms systemd-random-seed.service                                                              
   27ms resolvconf-pull-resolved.service                                                         
   26ms snapd.seeded.service                                                                     
   24ms plymouth-quit.service                                                                    
   23ms kerneloops.service                                                                       
   20ms systemd-tmpfiles-setup-dev.service                                                       
   18ms pppd-dns.service                                                                         
   18ms systemd-tmpfiles-clean.service                                                           
   17ms vboxweb.service                                                                          
   16ms hddtemp.service                                                                          
   14ms media-EvoData.mount                                                                      
   14ms plymouth-read-write.service                                                              
   14ms setvtrgb.service                                                                         
   13ms systemd-update-utmp.service                                                              
   13ms plymouth-start.service                                                                   
   12ms dev-hugepages.mount                                                                      
   11ms user-runtime-dir@1000.service                                                            
   11ms dev-mqueue.mount                                                                         
   11ms sys-kernel-debug.mount                                                                   
   10ms sys-kernel-tracing.mount                                                                 
   10ms systemd-user-sessions.service                                                            
    9ms systemd-remount-fs.service                                                               
    9ms tor.service                                                                              
    9ms ureadahead-stop.service                                                                  
    8ms kmod-static-nodes.service                                                                
    8ms systemd-sysctl.service                                                                   
    7ms ufw.service                                                                              
    5ms systemd-update-utmp-runlevel.service                                                     
    5ms console-setup.service                                                                    
    4ms sddm.service                                                                             
    4ms rtkit-daemon.service                                                                     
    3ms sys-fs-fuse-connections.mount                                                            
    3ms motd-news.service                                                                        
    3ms sys-kernel-config.mount                                                                  
    2ms ifupdown-pre.service                                                                     
    1ms snapd.socket                                                                             
lines 59-104/104 (END)

lhommegermelebien@lhommegermelebien-MS-7C02:~$ systemd-analyze critical-chain
The time when unit became active or started is printed after the "@" character.
The time the unit took to start is printed after the "+" character.

graphical.target @7.521s
└─multi-user.target @7.521s
  └─mysql.service @6.388s +1.131s
    └─network-online.target @6.384s
      └─NetworkManager-wait-online.service @2.982s +3.402s
        └─NetworkManager.service @2.704s +276ms
          └─dbus.service @2.701s
            └─basic.target @2.683s
              └─sockets.target @2.683s
                └─snapd.socket @2.681s +1ms
                  └─sysinit.target @2.674s
                    └─systemd-timesyncd.service @2.600s +74ms
                      └─systemd-tmpfiles-setup.service @2.329s +260ms
                        └─local-fs.target @2.325s
                          └─run-user-1000-gvfs.mount @18.091s
                            └─run-user-1000.mount @17.972s
                              └─swap.target @2.655s
                                └─dev-disk-by\x2duuid-afb66f97\x2d9f6c\x2d4cf2\x2db155\x2df0d114b10e5b.swap @2.606s +49ms
                                  └─dev-sda5.device @2.605s
lhommegermelebien@lhommegermelebien-MS-7C02:~$ 



lhommegermelebien@lhommegermelebien-MS-7C02:~$ ls -l /var/crash
total 22372
-rw-r----- 1 root whoopsie 22907829 janv. 18 00:22 _usr_lib_virtualbox_VirtualBoxVM.0.crash
Je ne vois pas de lenteur sur ces retours.

Il faudra attendre les conseils d'aidants plus expérimentés.
Merci Bluc pour ce dernier lien .
Je viens de controler a nouveau le temps : 45s pour accéder au pannaeu d'identification.

J'ai ouvert Gparted
Je trouve à l'avant dernière ligne du journal cette info "La partition « /dev/sda2 » n'est pas correctement alignée"
Est ce une erreur ?
2021-01-23 15:41:47: Utilisation du module externe de moteur : pmsfdiskbackendplugin (1)
2021-01-23 15:41:47: Analyse des périphériques...
2021-01-23 15:41:47: Périphérique trouvé : Samsung SSD 970 EVO Plus 1TB
2021-01-23 15:41:47: Périphérique trouvé : LDLC
2021-01-23 15:41:47: La partition « /dev/sda2 » n'est pas correctement alignée (premier secteur : 435410942, modulo : 2046).
2021-01-23 15:41:47: Analyse terminée.
Je m'emmèle les pinceaux ... Redonnons à Xubu 1957 ce qui lui revient et à Bluc aussi 🙂