read means as email comes in my eset scans it and the attachments if any for malware. I don't rescan existing email in existing folders or any new email I send out. MS Outlook is integrated (meaning using) eset as it's AV scanner. If you used another product that was integratable with MS Outlook then that would be used. My screeen shot came from Esets advanced settings tab which I suspect you have as well in your version of eset. Right click on my eset icon in task bar reveals it. The notion of rescanning old yet stored in folders likely email is that a email from the distant past may have slipped by and older version of eset and is lurking ready to get you. I know you hit one of those but I have to admit I don't worry on that matter. Looks like eset took care of yours anyway. I would turn off this historical scan thingy.... low low risk eats up too much at your end.