Hello again, I have finally managed to pin down the Bug in Apple Mail : - Go to Mail > Preferences - In the Accounts pane, click on your account and Modify - Modify the email address field (the one under "description") - for example add another address or delete the address - Click OK - Close Preferences If your Mac is like mine (G4 EMac running 10.2.3) then all the messages in your InBox will have disappeared - "poooof". And they are gone forever. Does anybody know how I can get them back ? Sorry Apple, but your Mail software is still a big piece of dragon poo...