is this consumer or enterprise version?
Ok will move the post to correct forum their FAQs /KB articles should explain extra dat running
post your version of enterprise as well please.
Also does this apply?
Simple answer : probably not, if your scans don't report anything. The extra.dat file was issued because of a high-risk threat that suddenly appeared (the autorun worm).
EXTRA.DAT files contain information that is used by VirusScan to detect a new virus. When a major virus is discovered and extra detection is required, an EXTRA.DAT file is made available until the normal VirusScan update is released.