Hello,
What version of SEP 12.1 are you running?
Was this SEP 12.1 from Migrated from the earlier version of SEP 11.x?
Is this issue occurying on 1 machine or all machines?
Incase, if this is occuring on 1 client machine, then
1) Uninstall SEP client along with Liveupdate.
2) Delete all Symantec directories and clear Temp directory
3) Restart the machine
4) Reinstall SEP client on the machine.
Hope that helps!!