I have a similiar issue with c::b on Win7 Professional and my Samsung Notebook. Wenn I am closing c::b, it allows me to save my work and the project settings but it won't shutdown itself, i.e. I must close c::b via task manager after then. This happens sporadically during my daily work but it is reproducable when I set my notebook in hibernation mode while c::b is running, waking it up again and try to close c::b.
Regards,
Deniz