Create a new client installation setting that resets client-server communications settings, and then deploy the Communication Update Package in the same way as clients: .
See About the Windows client installation settings for more information.
If the upgrade then fails, you can restore the Symantec Endpoint Protection Manager to functionality more quickly.
To recover an installation after a failure, due to database schema and other changes, you must reinstall using the exact version previously in use.
To get the latest security features, operating system support, and customer fixes, upgrade to the latest version.See Disaster recovery best practices for Symantec Endpoint Protection A: There are many methods available to upgrade clients.Second, decide which method is most appropriate for the situation.Ensure that you have made the proper exclusions to any peripheral firewall or proxy to ensure successful communication with all Symantec servers.See Required exclusions for proxy servers to allow Symantec Endpoint Protection to connect to Symantec reputation and licensing servers and Excluding a trusted Web domain from scans. Upgrading clients by using Auto Upgrade in Symantec Endpoint Protection You may want to schedule Auto Upgrade for after hours, due to possible bandwidth usage.