Bug appeared today on my up-to-date Oneiric. I can reproduce it easily. Let me know what info you need. $ gdb /usr/lib/unity/unity-panel-service GNU gdb (Ubuntu/Linaro 7.3-0ubuntu2) 7.3-2011.08 Copyright (C) 2011 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "i686-linux-gnu". For bug reporting instructions, please see: ... Reading symbols from /usr/lib/unity/unity-panel-service...(no debugging symbols found)...done. (gdb) run Starting program: /usr/lib/unity/unity-panel-service [Thread debugging using libthread_db enabled] Gtk-Message: Failed to load module "gail" ** (unity-panel-service:1742): DEBUG: Loading: /usr/lib/indicators3/6/libappmenu.so (unity-panel-service:1742): Indicator-Appmenu-DEBUG: New Desktop Window: 2A00004 [New Thread 0xb7d7fb70 (LWP 1745)] [New Thread 0xb757eb70 (LWP 1746)] ** (unity-panel-service:1742): DEBUG: Loading: /usr/lib/indicators3/6/libmessaging.so [New Thread 0xb6bffb70 (LWP 1747)] [New Thread 0xb63feb70 (LWP 1748)] (unity-panel-service:1742): libindicator-WARNING **: IndicatorObject class does not have an accessible description. ** (unity-panel-service:1742): DEBUG: Loading: /usr/lib/indicators3/6/libdatetime.so [New Thread 0xb4eb5b70 (LWP 1749)] (unity-panel-service:1742): Indicator-Datetime-DEBUG: Evaluating bitmask for '%H:%M' (unity-panel-service:1742): Indicator-Datetime-DEBUG: Checking against 1 possible times (unity-panel-service:1742): Indicator-Datetime-DEBUG: Guessing max time width: 36 ** (unity-panel-service:1742): DEBUG: Loading: /usr/lib/indicators3/6/libsoundmenu.so (unity-panel-service:1742): libindicator-WARNING **: IndicatorObject class does not have an accessible description. ** (unity-panel-service:1742): DEBUG: Loading: /usr/lib/indicators3/6/libpower.so (unity-panel-service:1742): libindicator-WARNING **: IndicatorObject class does not have an accessible description. ** (unity-panel-service:1742): DEBUG: Loading: /usr/lib/indicators3/6/libsession.so (unity-panel-service:1742): GLib-CRITICAL **: g_error_free: assertion `error != NULL' failed (unity-panel-service:1742): Indicator-Session-DEBUG: get entries ** (unity-panel-service:1742): DEBUG: Loading: /usr/lib/indicators3/6/libapplication.so ** (unity-panel-service:1742): DEBUG: Initializing PanelUtilAccessible class ** (unity-panel-service:1742): CRITICAL **: atk_object_set_description: assertion `description != NULL' failed ** (unity-panel-service:1742): CRITICAL **: atk_object_set_description: assertion `description != NULL' failed ** (unity-panel-service:1742): CRITICAL **: atk_object_set_description: assertion `description != NULL' failed (unity-panel-service:1742): Indicator-Session-DEBUG: get entries ** (unity-panel-service:1742): CRITICAL **: atk_object_set_description: assertion `description != NULL' failed ** (unity-panel-service:1742): DEBUG: Unity accessibility started, using bridge on /usr/lib/gtk-3.0/modules/libatk-bridge.so ** (unity-panel-service:1742): DEBUG: on_bus_acquired (unity-panel-service:1742): Indicator-Appmenu-DEBUG: Registering window ID 44040196 with path /com/canonical/menu/2A00004 from :1.39 (unity-panel-service:1742): Indicator-Appmenu-DEBUG: Creating new windows menu: 2A00004, :1.39, /com/canonical/menu/2A00004 (unity-panel-service:1742): Indicator-Appmenu-DEBUG: Setting Desktop Menus to: 2A00004 (unity-panel-service:1742): Indicator-Appmenu-DEBUG: Looking for parent window on XID 54525957 (unity-panel-service:1742): Indicator-Appmenu-DEBUG: Switching to menus from XID 54525957 ** (unity-panel-service:1742): WARNING **: on_indicator_menu_show() called with a NULL entry (unity-panel-service:1742): Indicator-Appmenu-DEBUG: Unable to get MWM functions for: 54525957 (unity-panel-service:1742): Indicator-Appmenu-DEBUG: Registering window ID 54525957 with path /com/canonical/menu/3400005 from :1.91 (unity-panel-service:1742): Indicator-Appmenu-DEBUG: Creating new windows menu: 3400005, :1.91, /com/canonical/menu/3400005 (unity-panel-service:1742): Indicator-Appmenu-DEBUG: Switching to menus from XID 54525957 ** (unity-panel-service:1742): DEBUG: Name Acquired (unity-panel-service:1742): Indicator-Datetime-DEBUG: notify visible signal received Program received signal SIGSEGV, Segmentation fault. 0x008435d8 in g_type_check_instance_cast () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 (gdb) bt #0 0x008435d8 in g_type_check_instance_cast () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #1 0x0048b88a in ?? () from /usr/lib/libgtk-3.so.0 #2 0x0081e9fa in g_cclosure_marshal_VOID__PARAM () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #3 0x0081ca5c in g_closure_invoke () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #4 0x00830ec0 in ?? () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #5 0x00839b8f in g_signal_emit_valist () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #6 0x00839d03 in g_signal_emit () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #7 0x0081fe1f in ?? () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #8 0x0081f17f in ?? () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #9 0x00822392 in g_object_notify () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #10 0x00421f0d in gtk_widget_show () from /usr/lib/libgtk-3.so.0 #11 0x0125e291 in ?? () from /usr/lib/libdbusmenu-gtk3.so.4 #12 0x0081ec6a in g_cclosure_marshal_VOID__OBJECT () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #13 0x0081ca5c in g_closure_invoke () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #14 0x00830ec0 in ?? () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #15 0x00839b8f in g_signal_emit_valist () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #16 0x00839d03 in g_signal_emit () from /usr/lib/i386-linux-gnu/libgobject-2.0.so.0 #17 0x0127804e in ?? () from /usr/lib/libdbusmenu-glib.so.4 #18 0x00706172 in g_simple_async_result_complete () from /usr/lib/i386-linux-gnu/libgio-2.0.so.0 #19 0x00764a8b in ?? () from /usr/lib/i386-linux-gnu/libgio-2.0.so.0 #20 0x00706172 in g_simple_async_result_complete () from /usr/lib/i386-linux-gnu/libgio-2.0.so.0 #21 0x00759a48 in ?? () from /usr/lib/i386-linux-gnu/libgio-2.0.so.0 #22 0x00706172 in g_simple_async_result_complete () from /usr/lib/i386-linux-gnu/libgio-2.0.so.0 #23 0x007062ac in ?? () from /usr/lib/i386-linux-gnu/libgio-2.0.so.0 #24 0x008a66e0 in ?? () from /lib/i386-linux-gnu/libglib-2.0.so.0 #25 0x008aa81f in g_main_context_dispatch () from /lib/i386-linux-gnu/libglib-2.0.so.0 #26 0x008aaf50 in ?? () from /lib/i386-linux-gnu/libglib-2.0.so.0 #27 0x008ab55b in g_main_loop_run () from /lib/i386-linux-gnu/libglib-2.0.so.0 #28 0x002ab805 in gtk_main () from /usr/lib/libgtk-3.so.0 #29 0x0804af46 in main ()