Not of any SEP 11.x version supported to Windows 8.
SEP 12.1 RU2 is the first version for Windows 8 support.
https://www-secure.symantec.com/connect/articles/latest-symantec-endpoint-protection-releases-symantec-endpoint-protection-121-ru2
12.1 RU3 is the latest one version for Windows 8 support.
https://www-secure.symantec.com/connect/blogs/latest-symantec-endpoint-protection-released-sep-121ru3
11.X is not supported
12.1.3 is the latest go with it.
http://www.symantec.com/business/support/index?page=content&id=TECH174348
Okies
11.x is not compaitble for Window8. 12.1.3 is compaitble version. Upgrade your version with 12.1.3