How to remove old virus alert from console?

Hey All,

I'm trying to remove an old trojan alert from my SEP 12.1.6 console running on Windows server 2012 the client machine that had the trojan is running OSX. I thought running a scan that didn't find the trojan would clear the alert. It seems that the folder with the trojan was deleted months ago, so SEP may not not have a record of the trojan being removed.

Thanks In Advance,