Another strange one. My wife just discovered that all emails in the Sent
Items between Jan 1, 2009 and May 28, 2009 are missing and I can't find them
anywhere. What could cause this?

We routinely archive all Sent Items from previous years in customized
folders like Saved Sent 2007 or Saved Sent 2008, hence the Jan 1, 2009 date
being the first one in the current Sent Items. She is running XP and IE 7.

Tom