You should only attempt these directions if you have your data backed up and are willing to risk creating additional problems.
You should also back up the Windows registry (see Windows - Backing up the Registry) before attempting any changes.
Upgrading Windows with 12.1.6 MP1 installed is supported according to Endpoint Protection product documentation.This issue occurs because additional Symantec Endpoint Protection upgrade processes have not completed.If you are able to connect but cannot install updates, try restarting your computer before continuing.Note: If you are unable to stop the Symantec Management Client you will need to temporarily disable Tamper Protection.The Do IT Help Desk is not liable if you choose to attempt the fix described below.
Before you begin troubleshooting Live Update, verify that you are able to connect to and browse
It is recommended that all Symantec products be uninstalled by using Add or Remove Programs before starting this process.
Log on as Administrator Manual removal of Symantec Endpoint Protection must be done from the Administrator account.
When the Administrator account is enabled, log on using that account.
Before you begin this procedure, back up the Windows registry.
CAUTION: This document includes instructions for modifying the registry on your computer.