After installation of SEP 12, many times clients protection found to be off.
task bar Icon also no available.
you need to start clients from START>All Programs> Symantec Endpoint Protection> aftre that it will ask yo to fix it, after clicking on fix all protection are fixed but still Task bar Icon does not came, you have to restart syatem to see it.
this happens during windows updates, System hibernation or many times their no reason.