Microsoft's antivirus deletes users' e-mails

Microsoft has admitted that its Live OneCare security suite has been accidentally deleting some users' Outlook and Outlook Express e-mails.

According to postings on Microsoft's OneCare forum, erasures have been caused when the antivirus program finds a virus in an e-mail attachment. Instead of then quarantining that single e-mail, users have reported that entire .pst or .dbx files -- the personal folder where non-Exchange Server users' messages and other details are kept -- have been quarantined or, in some cases, even deleted.

One user commented on the forum: "Is there a chance to recover it? If not, OneCare will have done more damage than any virus in my 30 years of active computing." Forum postings indicate, however, that recovery is possible in some cases, where the .pst or .dbx file is still available in OneCare's quarantine facility.

Stephen Boots, a forum administrator, commented that he was "very unhappy about this problem as it was reported over a year ago and fixed in the 1.0 release", adding: "It never appeared throughout the beta, but suddenly appeared when 1.5 was released".

In a statement reported on Computerworld, a Microsoft spokesperson confirmed that the company was "working to address an issue where the antimalware engine for OneCare is erroneously quarantining Outlook .pst files or Outlook Express .dbx files, when the .pst file or .dbx file contains an infected attachment". The spokesperson added that a fix would be included in the next OneCare update, which is due on 13 March.

OneCare has been hit this year by ongoing criticism, having only days ago failed to achieve certification in an independent test of security products. Shortly before that, it emerged that the product did not sufficiently protect users of Microsoft's Vista operating system against malware.

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David Meyer reported for ZDNet UK from London