The update was from 2.24 to 2.26. The error displays a big box about about 3 times when gdm is starting but before the desktop is displayed. Attaching .xsession-errors.
/etc/gdm/Xsession: Beginning session setup... SESSION_MANAGER=local/asusb202:@/tmp/.ICE-unix/5052,unix/asusb202:/tmp/.ICE-unix/5052 ** Message: couldn't set environment variable in session: The name org.gnome.SessionManager was not provided by any .service files 1248892690.236377 Session manager: disconnected... Window manager warning: Failed to read saved session file /home/dbrazziel/.config/metacity/sessions/default0.ms: Failed to open file '/home/dbrazziel/.config/metacity/sessions/default0.ms': No such file or directory GNOME_KEYRING_SOCKET=/tmp/keyring-9ppXjf/socket SSH_AUTH_SOCK=/tmp/keyring-9ppXjf/socket.ssh ** (gnome-volume-control-applet:5633): DEBUG: Disabling debugging
** (gnome-power-manager:5632): WARNING **: This machine is not identified as a laptop.system.formfactor is desktop. (nautilus:5619): Unique-DBus-WARNING **: Error while sending message: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken. ** (gnome-power-manager:5632): WARNING **: This machine is not identified as a laptop.system.formfactor is desktop. ** (gnome-power-manager:5632): DEBUG: This machine is not identified as a laptop.system.formfactor is desktop. ** (gnome-power-manager:5632): DEBUG: We are not a laptop, so not even trying ** (nautilus:5607): WARNING **: Unable to add monitor: Not supported 1248892708.009631 Session manager: disconnected... (gnome-panel:5605): Gdk-WARNING **: /build/buildd-gtk+2.0_2.16.1-2-i386-NWxSfb/gtk+2.0-2.16.1/gdk/x11/gdkdrawable-x11.c:878 drawable is not a pixmap or window (nautilus:5607): Gdk-WARNING **: gdk_xsettings_watch_cb(): Couldn't find window to unwatch VNC Viewer Free Edition 4.1.1 for X - built Jan 30 2009 19:33:16 Copyright (C) 2002-2005 RealVNC Ltd. See http://www.realvnc.com for information on VNC. Wed Jul 29 14:42:26 2009 CConn: connected to host localhost port 5902 CConnection: Server supports RFB protocol version 3.7 CConnection: Using RFB protocol version 3.7 Wed Jul 29 14:42:29 2009 TXImage: Using default colormap and visual, TrueColor, depth 24. CConn: Using pixel format depth 6 (8bpp) rgb222 CConn: Using ZRLE encoding CConn: Throughput 2807 kbit/s - changing to full colour CConn: Using pixel format depth 24 (32bpp) little-endian rgb888 ** (gnome-volume-control.pulse:7096): DEBUG: Disabling debugging ** (gnome-volume-control.pulse:7096): WARNING **: Unable to find stream for bar ** (gnome-volume-control.pulse:7377): DEBUG: Disabling debugging ** (gnome-volume-control.pulse:7377): WARNING **: Unable to find stream for bar evolution-shell-Message: Killing old version of evolution-data-server... ** (evolution:10995): DEBUG: mailto URL command: evolution %s ** (evolution:10995): DEBUG: mailto URL program: evolution evolution-shell-Message: Killing old version of evolution-data-server...