Esta é a coisa mais chata que eu já experimentei usando o Ubuntu 16.04 por 18 meses. Depois de uma atualização na semana passada, agora toda vez que eu passo pelos ícones de lançamento, Dash, ou simplesmente movo o mouse para o lado esquerdo da tela, tudo desaparece por cerca de quatro segundos e depois reaparece. Além disso, o desligamento não funciona, a área de trabalho pisca e fica livre de quaisquer ícones por quatro segundos e, em seguida, volta sem nenhuma caixa de diálogo para a seleção para a opção de reinicialização ou desligamento.
Eu li através dos problemas do Ubuntu semelhantes a isso, e reinstalei o ubuntu-deskptop, reinstalei a unidade, desinstalei e reinstalei o lightdm, movi e reinstalei os arquivos compiz, setsid unity, redefini o compizconfig-settings-manager e removi o .config. Nada funciona.
Aqui estão os resultados do comando debug unit:
$ unity --debug
unity-panel-service stop/waiting
unity7 stop/waiting
unity-panel-service start/running, process 4730
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
/usr/bin/compiz (core) - Info: Loading plugin: core
/usr/bin/compiz (core) - Info: Starting plugin: core
[New Thread 0x7ffff3637700 (LWP 4848)]
/usr/bin/compiz (core) - Info: Loading plugin: ccp
/usr/bin/compiz (core) - Info: Starting plugin: ccp
[New Thread 0x7fffeb20e700 (LWP 4852)]
compizconfig - Info: Backend : gsettings
compizconfig - Info: Integration : true
compizconfig - Info: Profile : unity
/usr/bin/compiz (core) - Info: Loading plugin: composite
/usr/bin/compiz (core) - Info: Starting plugin: composite
[New Thread 0x7fffea3e0700 (LWP 4853)]
/usr/bin/compiz (core) - Info: Loading plugin: opengl
/usr/bin/compiz (core) - Info: Starting plugin: opengl
/usr/bin/Compiz (opengl) - Info: GLX_EXT_buffer_age is supported
/usr/bin/compiz (core) - Info: Loading plugin: imgpng
/usr/bin/compiz (core) - Info: Starting plugin: imgpng
/usr/bin/compiz (core) - Info: Loading plugin: wall
/usr/bin/compiz (core) - Info: Starting plugin: wall
/usr/bin/compiz (core) - Info: Loading plugin: compiztoolbox
/usr/bin/compiz (core) - Info: Starting plugin: compiztoolbox
/usr/bin/compiz (core) - Info: Loading plugin: grid
/usr/bin/compiz (core) - Info: Starting plugin: grid
/usr/bin/compiz (core) - Info: Loading plugin: copytex
/usr/bin/compiz (core) - Info: Starting plugin: copytex
/usr/bin/compiz (core) - Info: Loading plugin: place
/usr/bin/compiz (core) - Info: Starting plugin: place
/usr/bin/compiz (core) - Info: Loading plugin: regex
/usr/bin/compiz (core) - Info: Starting plugin: regex
/usr/bin/compiz (core) - Info: Loading plugin: resize
/usr/bin/compiz (core) - Info: Starting plugin: resize
/usr/bin/compiz (core) - Info: Loading plugin: mousepoll
/usr/bin/compiz (core) - Info: Starting plugin: mousepoll
/usr/bin/compiz (core) - Info: Loading plugin: commands
/usr/bin/compiz (core) - Info: Starting plugin: commands
/usr/bin/compiz (core) - Info: Loading plugin: vpswitch
/usr/bin/compiz (core) - Info: Starting plugin: vpswitch
/usr/bin/compiz (core) - Info: Loading plugin: animation
/usr/bin/compiz (core) - Info: Starting plugin: animation
/usr/bin/compiz (core) - Info: Loading plugin: move
/usr/bin/compiz (core) - Info: Starting plugin: move
/usr/bin/compiz (core) - Info: Loading plugin: unitymtgrabhandles
/usr/bin/compiz (core) - Info: Starting plugin: unitymtgrabhandles
/usr/bin/compiz (core) - Info: Loading plugin: snap
/usr/bin/compiz (core) - Info: Starting plugin: snap
/usr/bin/compiz (core) - Info: Loading plugin: session
/usr/bin/compiz (core) - Info: Starting plugin: session
/usr/bin/compiz (core) - Info: Loading plugin: expo
/usr/bin/compiz (core) - Info: Starting plugin: expo
/usr/bin/compiz (core) - Info: Loading plugin: ezoom
/usr/bin/compiz (core) - Info: Starting plugin: ezoom
/usr/bin/compiz (core) - Info: Loading plugin: fade
/usr/bin/compiz (core) - Info: Starting plugin: fade
/usr/bin/compiz (core) - Info: Loading plugin: workarounds
/usr/bin/compiz (core) - Info: Starting plugin: workarounds
/usr/bin/compiz (core) - Info: Loading plugin: scale
/usr/bin/compiz (core) - Info: Starting plugin: scale
/usr/bin/compiz (core) - Info: Loading plugin: unityshell
/usr/bin/compiz (core) - Info: Starting plugin: unityshell
[New Thread 0x7fffcbd09700 (LWP 4866)]
WARN 2018-01-12 15:18:09 unity.glib.dbus.server GLibDBusServer.cpp:593 Can't register object 'org.gnome.Shell' yet as we don't have a connection, waiting for it...
WARN 2018-01-12 15:18:09 unity.debug.interface DebugDBusInterface.cpp:217 Unable to load entry point in libxpathselect: libxpathselect.so.1.4: cannot open shared object file: No such file or directory -- full D-Bus introspection will not be available
WARN 2018-01-12 15:18:10 xim.controller XIMController.cpp:103 IBus natively supported.
WARN 2018-01-12 15:18:10 unity.dash.gsettingsscopereader GSettingsScopes.cpp:108 Error fetching protocol metadata for scope: social.scope : Valid key file could not be found in search dirs
WARN 2018-01-12 15:18:10 unityct(io) <unknown>:0 Desktop file '/usr/share/applications/zim.desktop' is using a deprecated format for its actions that will be dropped soon.
WARN 2018-01-12 15:18:10 unity.glib.dbus.server GLibDBusServer.cpp:593 Can't register object 'com.canonical.Unity.Launcher' yet as we don't have a connection, waiting for it...
WARN 2018-01-12 15:18:10 unity.glib.dbus.server GLibDBusServer.cpp:593 Can't register object 'com.canonical.Unity.Dash' yet as we don't have a connection, waiting for it...
WARN 2018-01-12 15:18:10 unity.glib.dbus.server GLibDBusServer.cpp:593 Can't register object 'org.gnome.SessionManager.EndSessionDialog' yet as we don't have a connection, waiting for it...
WARN 2018-01-12 15:18:10 unity.glib.dbus.server GLibDBusServer.cpp:593 Can't register object 'com.canonical.Unity.Session' yet as we don't have a connection, waiting for it...
WARN 2018-01-12 15:18:10 unity.glib.dbus.server GLibDBusServer.cpp:593 Can't register object 'org.gnome.ScreenSaver' yet as we don't have a connection, waiting for it...
ERROR 2018-01-12 15:18:12 unity.glib.dbus.server GLibDBusServer.cpp:538 DBus name lost 'org.gnome.Shell'
ERROR 2018-01-12 15:18:12 unity.glib.dbus.server GLibDBusServer.cpp:538 DBus name lost 'com.canonical.Unity'