I think I might have fixed this problem myself. Tools/accounts/mail/properties/advanced then untick "leave a copy of message on server" So far it has worked, only one copy appears in my window mail now. Long may it last. Carol
If you want to keep your emails on the email server (eg to access them using Webmail, eg if you have a googlemail, yahoo, etc, email address) try ticking it again - you may find that the problem is now fixed.