You need to manually download definitions for the Cloud version of Symantec Endpoint Protection Small Business Edition (SEP SBE) client or group(s) of clients.
From customer portal (https://hostedendpoint.spn.com) to entire Group(s):
For a specific Windows XP(x86), Windows Vista, Windows 7, Windows 8/8.1 computer:
For a specific Server 2003, 2008, 2012 computer:
For a specific computer with an Intelligent Updater .exe package:
Rapid Release Definitions for a specific computer:
For a Mac OS computer:
While there isn't a manual way to update the definitions separately, you can force a refresh of the definitions by removing Symantec software for Mac OS using RemoveSymantecMacFiles, then re-installing the program onto the Mac device.