By default, LiveUpdate is scheduled to run daily in order to keep your computer up to date with the latest virus definitions and software updates for Symantec Endpoint Protection. If you would like to make sure your computer has the latest definitions and updates you can run LiveUpdate manually. This might be useful if your computer has not been connected to the Internet or turned on for some time.
STEP 1: Open Symantec Endpoint Protection by going to Start -> All Programs -> Symantec Endpoint Protection -> Symantec Endpoint Protection.
STEP 2: Click LiveUpdate.
STEP 3: Wait for LiveUpdate to finish downloading and installing updates automatically.