I have an email account that supports IMAP and I also have a Gmail account. I want to import a folder from the email account that supports IMAP to Gmail (my sent messages folder).

This Lifehacker article suggests a solution for that. Basically, you take a mail client, set up IMAP for both Gmail and the account, and then drag the folder into the Gmail account. This sounds okay, but the thing is that I want the Sent folder to be synchronized with the Gmail account.

I don't mind every once in a while dragging the Sent folder to Gmail folder manually, but my question is - will it create duplicates from the Sent folder in the Gmail account?

  • looks like you've already got your answer down there... and probably by trying it yourself too (since you never came back)! :D
    – cregox
    Oct 9, 2010 at 20:10
  • i tried this method many times, and gmail will not create duplicate. In fact I had tons of dups in my old outlook db, and instead of trying buggy software to remove dups, I just moved everything to gmail, which cleaned everything for me.
    – user14485
    Nov 3, 2011 at 17:11

3 Answers 3


Google's duplicate matching is based on the Message-ID: header. As long as they're truly the same message duplicates will not be created.


Gmail is pretty good at preventing duplicate messages. In fact it is so good that it will even sometimes eliminate non-duplicate messages. For example, if you send the same exact email twice (same 'from', 'to', 'subject', and 'body') to a Gmail account (within a few minutes or so), it will only appear once in the receiving Gmail account.

So my guess is that it will not produce duplicates. However, I haven't tried lifehacker's method, so I can't say for sure.


For the specific problem of keeping a Gmail-searchable archive of sent mail, I suggest an alternate solution:

Use Gmail as your SMTP server. You can do this entirely independently of using a separate IMAP server for your incoming mail. I have done this for years. Your mail client will still store a copy of every sent message in the sent folder on your IMAP account, just as before, but now Gmail keeps every sent message just as though you sent it from Gmail.

You can still set your "From" address to any address which is registered as an alternate in your Gmail account.

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