right click the folder, select properties and then the repair button. See if it is just an indexing issue that way.

Thanks Matt, I did what you said and now they are all gone. Anyway to bring them back?

I thought that might happen. Check your anti virus program logs for actions on a file with the same name as the folder in Thunderbird. Sometime it is corruption. But more often the anri virus has deleted or quarantined the store file.

Norton has no email errors listed ever in the log files

Oh well, I guess they are gone on this computer. My laptop has not accessed the email server in a long time. I'm sure they will download again if push comes to shove. Still, kinda makes me nervous using Thunderbird without knowing what happened.

Your not lg for an email event in NIS. Your looking for a file with the same name as the Thunderbird folder.

NIS scans your mail storage folders, detects something in the file that may have been there for 2 years and immediately identifies it a a threat. When you click for it to do something about it automatically, it deletes the file. I have tried to address this very issue with the folk at Symantec. What I was told is as I do not have a Mozilla email address and I am not a customer they would not communicate with me. So all I can do is warn people about the product and let them make their own decisions.