Having the same problem, but I cannot find a reproducable set of steps... yet. Compiz segfaults in libregex library: Versions, from natty: $ COLUMNS=160 dpkg -l | grep compiz ii compiz 1:0.9.2.1+glibmainloop4-0ubuntu3 OpenGL window and compositing manager ii compiz-core 1:0.9.2.1+glibmainloop4-0ubuntu3 OpenGL window and compositing manager ii compiz-dev 1:0.9.2.1+glibmainloop4-0ubuntu3 OpenGL window and compositing manager - development files ii compiz-fusion-plugins-extra 0.9.2.1-0ubuntu2 Collection of extra plugins from OpenCompositing for Compiz ii compiz-fusion-plugins-main 0.9.2.1-0ubuntu7 Compiz Fusion plugins - main collection ii compiz-gnome 1:0.9.2.1+glibmainloop4-0ubuntu3 OpenGL window and compositing manager - GNOME window decorator ii compiz-plugins 1:0.9.2.1+glibmainloop4-0ubuntu3 OpenGL window and compositing manager - plugins ii compizconfig-backend-gconf 0.9.2.1git101213-0ubuntu1 Compiz Fusion configuration system - gconf backend ii compizconfig-settings-manager 0.9.2.1-0ubuntu1 Compiz configuration settings manager ii libcompizconfig0 0.9.2.1git101125-0ubuntu4 Settings library for plugins - OpenCompositing Project ii libcompizconfig0-dev 0.9.2.1git101125-0ubuntu4 Development file for plugin settings - OpenCompositing Project ii python-compizconfig 0.9.2.1-0ubuntu2 Compizconfig bindings for python GDB backtrace... $ gdb --args compiz --replace GNU gdb (GDB) 7.1-ubuntu Copyright (C) 2010 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 "x86_64-linux-gnu". For bug reporting instructions, please see: ... Reading symbols from /usr/bin/compiz...(no debugging symbols found)...done. (gdb) run Starting program: /usr/bin/compiz --replace [Thread debugging using libthread_db enabled] No value set for `/apps/compiz-1/general/allscreens/options/active_plugins' [New Thread 0x7ffff1e1a710 (LWP 18056)] Backend : gconf Integration : true Profile : default Adding plugins Initializing core options...done Initializing bailer options...done Initializing detection options...done Initializing composite options...done Initializing opengl options...done Initializing decor options...done /usr/bin/compiz (core) - Warn: Value type is not yet set Initializing resize options...done Initializing imgjpeg options...done Initializing place options...done Initializing snap options...done Initializing session options...done Initializing move options...done Initializing mousepoll options...done Initializing imgsvg options...done Initializing gnomecompat options...done Initializing winrules options...done Initializing resizeinfo options...done Initializing animation options...done Initializing ring options...done Initializing wall options...done Initializing workarounds options...done Initializing animationaddon options...done Initializing fade options...done Initializing expo options...done Initializing ezoom options...done Initializing scale options...done Initializing scaleaddon options...done Setting Update "shadow_radius" Setting Update "shadow_x_offset" Setting Update "command" Setting Update "mipmap" Setting Update "decoration_match" Setting Update "shadow_match" Setting Update "mode" Setting Update "position_matches" Setting Update "position_x_values" Setting Update "position_y_values" Setting Update "position_constrain_workarea" Setting Update "above_match" Setting Update "fade_time" Setting Update "always_show" Setting Update "close_effects" Setting Update "close_durations" Setting Update "shade_durations" Setting Update "glide2_away_position" Setting Update "prev_key" Setting Update "speed" Setting Update "timestep" Setting Update "thumb_width" Setting Update "thumb_height" Setting Update "explode_gridx" Setting Update "explode_gridy" Setting Update "explode_spokes" Setting Update "explode_tiers" Setting Update "expo_edge" Setting Update "zoom_time" Setting Update "vp_distance" Setting Update "hide_docks" Setting Update "mipmaps" Setting Update "multioutput_mode" Setting Update "ground_size" Setting Update "zoom_in_button" Setting Update "zoom_out_button" Setting Update "zoom_mode" Setting Update "scale_mouse_static" Setting Update "restrain_mouse" Setting Update "follow_focus" Setting Update "speed" Setting Update "overlay_icon" Setting Update "initiate_edge" Setting Update "title_bold" Setting Update "title_size" Setting Update "border_size" Setting Update "layout_mode" Setting Update "natural_precision" constraining to 0 constraining to 0 constraining to 0 constraining to 0 Program received signal SIGSEGV, Segmentation fault. 0x00007fffeca991c5 in RegexExp::evaluate(CompWindow*) () from /usr/lib/compiz/libregex.so (gdb) bt #0 0x00007fffeca991c5 in RegexExp::evaluate(CompWindow*) () from /usr/lib/compiz/libregex.so #1 0x000000000044758f in ?? () #2 0x000000000044754b in ?? () #3 0x00007fffedb66904 in DecorWindow::update(bool) () from /usr/lib/compiz/libdecor.so #4 0x00007fffedb69416 in DecorWindow::DecorWindow(CompWindow*) () from /usr/lib/compiz/libdecor.so #5 0x00007fffedb6c8f9 in CompPlugin::VTableForScreenAndWindow::initWindow(CompWindow*) () from /usr/lib/compiz/libdecor.so #6 0x000000000044fbf5 in CompPlugin::windowInitPlugins(CompWindow*) () #7 0x0000000000441499 in CompWindow::CompWindow(unsigned long, unsigned long) () #8 0x000000000044e8cd in CompScreen::handleEvent(_XEvent*) () #9 0x00007ffff07b8ef4 in PrivateCompositeScreen::handleEvent(_XEvent*) () from /usr/lib/compiz/libcomposite.so #10 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #11 0x00007ffff018cc3f in PrivateGLScreen::handleEvent(_XEvent*) () from /usr/lib/compiz/libopengl.so #12 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #13 0x00007fffedb67d53 in DecorScreen::handleEvent(_XEvent*) () from /usr/lib/compiz/libdecor.so #14 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #15 0x00007fffed715e86 in ResizeScreen::handleEvent(_XEvent*) () from /usr/lib/compiz/libresize.so #16 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #17 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #18 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #19 0x00007fffecca9220 in SessionScreen::handleEvent(_XEvent*) () from /usr/lib/compiz/libsession.so #20 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #21 0x00007fffeca9934f in RegexScreen::handleEvent(_XEvent*) () from /usr/lib/compiz/libregex.so #22 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #23 0x00007fffec67d60c in MoveScreen::handleEvent(_XEvent*) () from /usr/lib/compiz/libmove.so #24 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #25 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #26 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #27 0x00007fffe8d8a03d in WorkaroundsScreen::handleEvent(_XEvent*) () from /usr/lib/compiz/libworkarounds.so #28 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #29 0x00007fffe8927521 in FadeScreen::handleEvent(_XEvent*) () from /usr/lib/compiz/libfade.so #30 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #31 0x00007fffe8041177 in PrivateScaleScreen::handleEvent(_XEvent*) () from /usr/lib/compiz/libscale.so #32 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #33 0x00007fffe7e19dfa in ScaleAddonScreen::handleEvent(_XEvent*) () from /usr/lib/compiz/libscaleaddon.so #34 0x000000000044db2b in CompScreen::handleEvent(_XEvent*) () #35 0x000000000042de1b in PrivateScreen::processEvents() () #36 0x0000000000454548 in CompEventSource::callback() () #37 0x00007ffff6e438ef in Glib::Source::dispatch_vfunc(_GSource*, int (*)(void*), void*) () from /usr/lib/libglibmm-2.4.so.1 #38 0x00007ffff4dffd0d in g_main_context_dispatch () from /lib/libglib-2.0.so.0 #39 0x00007ffff4e004f8 in ?? () from /lib/libglib-2.0.so.0 #40 0x00007ffff4e00b3a in g_main_loop_run () from /lib/libglib-2.0.so.0 #41 0x0000000000429b8a in CompScreen::eventLoop() () ---Type to continue, or q to quit--- #42 0x0000000000422c50 in main () (gdb) cont Continuing. [Thread 0x7ffff1e1a710 (LWP 18056) exited] Program terminated with signal SIGSEGV, Segmentation fault. The program no longer exists. (gdb) q