Hello,
What version of SEP 12.1 client are you running on the client machine?
What OS is this issue occurying on ?
As per the Screenshot, you are facing an issue - "Event ID 13 - Liveupdate returned a non-critical error. Available contents updates may have failed to install."
I would suggest you to follow the Articles below:
How to clear out definitions for a Symantec Endpoint Protection 12.1 client manually
http://www.symantec.com/docs/HOWTO59193
Event ID 13: "SescLU - LiveUpdate returned a non-critical error. Available content may have failed to install."
http://www.symantec.com/docs/TECH91615
Hope that helps!!