I'm using Mail (the Mac OS X app, v4.5) to access my Google Mail account, but every mail sent to my Gmail address arrives twice in Mail. In the global inbox for the Gmail accountAnd one in the IMAP folder for the Gmail account in the All messages folder(In my German version it's the Alle Nachrichten folder)I thought it was because I used filters and labels in Gmail to pre-organize my Mail, but I disabled both filters and labels and the issue still persists.  I want to avoid deleting the All messages folder in Mail since I'm afraid I won't be able to access all my mails in my Gmail account from Mail anymore.  Is this a known issue? I know people who use Gmail with Mail who don't have this problem, but I couldn't find out what they had set differently.EDIT: It appears matthiasr is right. Apple Mail simply can't handle Gmail. I tried Sparrow, another e-Mail client for Mac which can, however, handle GMail quite nicely.  Works like a charm.  Unless anyone can provide a workaround of some sort for Apple Mail, I would mark matthiasr's answer as accepted.
Duplicate e-Mails in Mail (Mac OS X) in GMail inbox
email;mac;gmail imap
This is the expected behaviour of GMail via IMAP, and is documented here.The underlying problem is that the GMail paradigm of having one gigantic pile of mail (All Mail) with tags (and INBOX is just another tag, just one that every new message has attached) does not map well to the folder paradigm underlying IMAP.Inside GMail, it's completely normal to have a mail show up in Inbox, All Mail and a bunch of other tags as well. IMAP clients (including Apple Mail) don't really expect this and do not realize that these are the same message.Not much you can do about it, other than hiding the [GMail] hierarchy of folders.