Missing Inbox Contents

Hi,

I have an Exchange 2000 Server running on a Win 2000 SB Server. SP3. Roaming Profiles and Active Directory.

I have recently started having users complain that the emails in their mailboxes are disappearing as well as contacts.
Logging the user off will generally restore the emails etc, but most recently there was nothing that would work, until i rebooted the server.

Now i have scrolled through MS website (useless), and several other sites and have had no luck at all in finding out why this is happening or what a solution would be as obviously i am not going to reboot the server everytime!!

Any help would be much appreciated!!

Regards

Psya