Sending mails via Mutt and Gmail: Duplicates

I'm trying to set up Mutt with GMail for the first time. It seems to work pretty well. However, when I send a mail from Mutt, it appears twice in GMail's Sent folder. (I assume it's also sent twice - I'm trying to validate that.)

My configuration (Stripped of coloring):

# A basic .muttrc for use with Gmail
# Change the following six lines to match your Gmail account details
set imap_user = "XX"
set smtp_url = "[email protected]@smtp.gmail.com:587/"
set from = "XX"
set realname = "XX"

# Change the following line to a different editor you prefer.
set editor = "vim"

# Basic config, you can leave this as is
set folder = "imaps://imap.gmail.com:993"
set spoolfile = "+INBOX"
set imap_check_subscribed
set hostname = gmail.com
set mail_check = 120
set timeout = 300
set imap_keepalive = 300
set postponed = "+[Gmail]/Drafts"
set record = "+[Gmail]/Sent Mail"
set header_cache=~/.mutt/cache/headers
set message_cachedir=~/.mutt/cache/bodies
set certificate_file=~/.mutt/certificates
set move = no
set include
set sort = 'threads'
set sort_aux = 'reverse-last-date-received'
set auto_tag = yes
hdr_order Date From To Cc
auto_view text/html
bind editor <Tab> complete-query
bind editor ^T complete
bind editor <space> noop

# Gmail-style keyboard shortcuts
macro index,pager y "<enter-command>unset trash\n <delete-message>" "Gmail archive message"
macro index,pager d "<enter-command>set trash=\"imaps://imap.googlemail.com/[Gmail]/Bin\"\n <delete-message>" "Gmail delete message"
macro index,pager gl "<change-folder>"
macro index,pager gi "<change-folder>=INBOX<enter>" "Go to inbox"
macro index,pager ga "<change-folder>=[Gmail]/All Mail<enter>" "Go to all mail"
macro index,pager gs "<change-folder>=[Gmail]/Starred<enter>" "Go to starred messages"
macro index,pager gd "<change-folder>=[Gmail]/Drafts<enter>" "Go to drafts"
macro index,pager gt "<change-folder>=[Gmail]/Sent Mail<enter>" "Go to sent mail"

#Don't prompt on exit
set quit=yes


## =================
#Color definitions
## =================

set pgp_autosign

To get rid of duplicates, unset $record. Gmail's SMTP server stores the message automatically.

Don't save sent messages, Gmail has that function inbuilt, set record = "+[Gmail]/Sent Mail" is unnecessary (and causes the issue you describe).

The Gmail server automatically stores a copy of all sent mail for you, so you do not need mutt to also store a copy. You want to keep the $record setting as that allows you to view the sent folder from mutt via the < shortcut. What you want to do is to set $copy to no to disable mutt's storing of all sent mail:

set record = "+[Gmail]/Sent Mail"
set copy = no

And no, the emails were not actually sent to the recipients twice.

Via: http://mail.google.com/support/bin/answer.py?hl=en&answer=78892

Do NOT save sent messages on the server. If your client is sending mail through Gmail's SMTP server, your sent messages will be automatically copied to the [Gmail]/Sent Mail folder.