Andy Chase

Finally, after finding fragments of the necessary code hither and yon across the aether, I pieced together the steps necessary to kill duplicate messages in Mail.app. I keep winding up with multiple copies of old messages in Mac OS X (Panther) Mail when, for some reason, either the server or the mail app itself decides it's time to re-download hundreds of previous emails every month or so.

The example here partially fixes a broken script in a comment on Macosxhints.com, but I was still having trouble with it. Finally, this is what I came up with that seemed to work.



(For the love of pete, back up all of your mail before doing anything like this. Attempt this at your own risk, I disavow all responsibility for lost data, et cetera.)



Create a shell script wherever it is you like to put shell scripts, say /usr/local/bin, and name it something like maildedupe.sh. Be sure to chmod so as to be executable. In the script, put the following:

#!/bin/sh                                                                                                        
echo "Deduping $1..."                                                                                            
formail -D 1000000 idcache  '$1.ztmp' && mv '$1.ztmp' '$1'                                              
rm idcache

This is basically the same as Jeremy's script linked above, with a couple of improvements:

1. single quotes around mailbox filenames keep the script from breaking if you happen to have a mailbox with a space in its name.
2. using '$1.ztmp' instead of 'ztmp' assures that the temp file will be created in the same place as the mailbox being deduped.

To auto-run this script an all of your mailboxes automagically (You did back them up, right?), go to the terminal, and type

cd ~/Library/Mail

Then type:

find . -name 'mbox' -exec /usr/local/bin/maildedupe.sh {} \;

All of the affected messages will suddenly appear as being unread, but at least you won't have more than one copy of each any more.