I have SEP 12 (Version 12.1.2015.2015) on a test workstation. It lost communication, but when I was attempting to replace Sylink.xml, I was unable to find the directory where Sylink.xml is located.
How to replace Sylink.xml on a SEP 12 client?
Navigate to the SEP install folder on the client. In the Bin folder is sylinkdrop.exe
Run that and select the sylink.xml file and click OK. Should than replace.
"Thumbs Up" to Brian above. Just for reference, I think the sylink.xml file is now in:
%ProgramData%\Symantec\Symantec Endpoint Protection\CurrentVersion\Data\Config