I have spent quite some time now Googling this and reading any number of different 'solutions', but none of them in the end applied to me (Rules problem (none for the account in question), Outlook downloading headers only.. etc. etc.).

I have multiple accounts on my Outlook 2007. Two of them are IMAP - one of which immediately produces two copies of exactly the same email whenever I check for new emails. (The other IMAP account never does this, I just get one message).

Any ideas what could be causing this in one IMAP account but not the other? I can't see anything in Properties that is any different. (There's no 'Leave copy on server' option for IMAP of course).

Many thanks.