While installing/updating file 1 of 2 using LiveUpdate on an Intel iMac running Mavericks, installation failed with the resulting error message "There was an error performing the update". Then, one started to manually install the virus definitions from Symantec web page http://www.symantec.com/security_response/definitions/download/detail.jsp?gid=nmc . During the start of the installation process it was indicated that an XCode command line utility was needed to complete the process. As a result, one clicked on the displayed dialog box Install Xcode button and XCode succesfully installed from Apple's App Store. After XCode installation, the LiveUpdate process was then successfully performed using the LiveUpdate manager (from menu). It is strange that the installation of more than 2 GB of Xcode is required for LiveUpdate to function properly.
I do not need a solution (just sharing information)