Xfce no panel

It doesn't happen often (but I'd love to know why), but I lost by Xfce panel again today. Luckily this is easy to fix. Open a terminal (right mouse click) and re-start the panel with:

xfce4-panel &

Now that you have you're panel working make this permanent by removing current session information:

rm -rf ~/.cache/sessions/

Logout and restart your session.
One final hint, backup your Xfce4 settings! I alias the backup command and keep a local and remote copy of the generated archive:

alias backupxfce='cd ~;tar jcvf Backups/xfce4.tar.bz2 .config/xfce4'

This alias will create a bzip2 archive.