Symantec LiveUpdate keeps your Symantec Endpoint Protection virus definitions up-to-date. It obtains Symantec program and protection updates for your computer through your Internet connection. Program updates are usually created to extend the operating system or hardware compatibility, adjust a performance issue, or fix program errors. Symantec releases program updates on an as-needed basis.

LiveUpdate locates and obtains files from a website, installs them, and then deletes the remaining files from your computer. Protection updates are the files that keep your Symantec Endpoint product up-to-date with the latest threat protection technology. By default, LiveUpdate runs automatically at scheduled intervals. Based on your security settings, you can run LiveUpdate manually by going into the Symantec client and clicking on the LiveUpdate link in the sidebar. You may also choose to disable LiveUpdate or change its update schedule.

Manually updating virus definitions

*For Managed Machines this

Mac:

1. Open Symantec EndPoint Protection from the gold shield next to your clock at the top right of your screen
   
2. Click on the LiveUpdate Now button at the bottom of the screen
   

Windows: 

1. Click on the gold shield in the system tray (next to your clock at the bottom right of your screen)
   
2. The User Account Control prompt will appear asking you if you want to make changes to this computer.  Click Yes.
   
3. Click on LiveUpdate