I received this distress call from a remote user today. I wondered how she had managed to uninstall Outlook, but, in fact, it was Outlook.PST which was utterly missing from her machine. After some head scratching and log diving, we found that OneCare had quarantined it--not as part of a tune-up, but just routine operation in the evening while the owner was nowhere near the machine.OneCare being the Microsoft all-in-one security and performance doohicky.
Outlook.PST is the file where your mail is. Not 'a' message but the entire shooting match.
More users chime in with 'hey that happened to me' and there are hints for keeping it from happening. Again.
Aparently, upon finding a virus in a downloaded e-mail, OneCare decided to quarantine not the single message, but the entire Outlook Express file that contained the infected attachment, whatever small nuisance it was. When for some reason it was not able to quarantine (probably because Outlook Express is running 24/7), it decided it better erase the whole file that includes my entire 4 months of business transactions (and the damage would have been years' worth had I not backed up). Yeah, I mean, why not, if you cannot extract one single message, better delete the entire 4000 of them?!
As if it's normal for your computer to just delete email - it happens all the time! - it's a feature! - and you have to be a brain dead moron to not tell your AV software "hey don't nuke the important stuff".